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Default Excitation of 65 Kva Alternator

I posted this on an Electrical Engineering Group, but no one knew
there, - does anyone know here ?

I have had a very big 3 phase 415v 50 c/s alternator for years now
and
at last I need to put it into service.

It was manufactured by Mawdsley in the early 80s and when I shut it
down, I disconnected the AVR too and kept this and the spare I held.
I have checked with the Company and there is no way that they can
help
me with the excitation to fire it up. Before I go to all the trouble
of connecting it up to a diesel engine and spin it up to 1500 rpm,
can
anyone please tell me a few things about it.


It has a separate excitation generator on the end of the shaft and I
would imagine that this is still in circuit, as I have not been
inside
it yet. How does this set up actually work. does the alternator self
excite and the AVR just keep the output within narrow and automatic
limits? Will it produce 3 phase on it's own or is the AVR essential
and in this case is it a standard wiring circuit or will it be unique
to this alternator and AVR setup?


There is quite a lot of information on the makers plates on the two
units, but no information on how to connect it all up. The AVR
itself
has a whole lot of wire connections available but nothing to tell me
what goes where. I have spent hours looking for information on the
web, but with no luck.


This is what I wrote to the manufacturer:


Thanks for any comments, It really is a super machine. a bit dirty
now
but that will be easy to rectify.


Regards George.


I have had a closer look at the big alternator - which is the one
that
I
really would like to see working again. There are two units, the
main
alternator body which has the following information:


Mawdsley A/C Generator BS 2613?70 (there is a scratch across the
number)
ser. no. 4FA4KB. 501
KVA 65 ( I thought it was 85, but this is better really as my
engines
would
be struggling at 85 KVA.)
Volts 415. Amps 90. 3 Phase. conn. star. rpm 1500.
Excitation volts 71. amps 18 pf. 0.8 enclosure SP?


Then on the excitation generator there is another label:
Exciter BS 2613/70
No. 6R4N3155 rpm 1500 volts 71 amps 18 3 phase hz 50.
Exc. volts 16.5, amps 1.8, ins. class F.


I have two identical voltage regulator boxes made by Emrec but with
your Co.
name on too. Type 4VR ser. no. 1197 (one of them)
30 VDC. 6 Amps.


I am not sure about this, but am I correct in assuming that the
voltage
regulator feeds into the exciter and this is internally fed into the
main
alternator? If so and if the 4VR is the one for this alternator,
then
all I
have to do is wire it up and I do have the connections for the 400 Hz
alternator to another voltage regulator 6VR I think they are,I have
two of
these too. I have a small number of explanatory sheets in how the 400
Hz
machines work with their AVRs If you can confirm the 4VR is the one
for the
65 KVR 50 HZ machine I think I will be OK.


Hoping this makes sense to you and that you can shine some light on
the
situation. I wish I knew more on how excitation works - or worked 30
years
ago! Would it be true to say that most alternators use the same sort
of
excitation, and only the details are different between manufacturers?
If
the voltage output of an alternator is only dependant on the loading
and the
DC current being fed into the excitation winding of the exciter, it
may be
that I can build a circuit that does this in a very simple way. My
load is
not going to be anywhere near 65 KVA in any case.


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Default Excitation of 65 Kva Alternator


"George" wrote in message
...
I posted this on an Electrical Engineering Group, but no one knew
there, - does anyone know here ?

I have had a very big 3 phase 415v 50 c/s alternator for years now
and
at last I need to put it into service.

It was manufactured by Mawdsley in the early 80s and when I shut it
down, I disconnected the AVR too and kept this and the spare I held.
I have checked with the Company and there is no way that they can
help
me with the excitation to fire it up. Before I go to all the trouble
of connecting it up to a diesel engine and spin it up to 1500 rpm,
can
anyone please tell me a few things about it.


The best thing to do, is fire it up. Get it spinning and see sort of thing.

The Auto' Volt' Reg' will be regulating both internal and output supplies, I
would have thought. Also, If you can't see any sort of external bridging
between the units, then it would seem that the AVR would already be
connected and ready to go.

The other Regulators sound like drop downs for external low voltage supply,
maybe from the AVR to sensors on the exciter, to check the main output and
automatically adjust engine speed Etc.

Can you post pictures for us?

Have you read anything like this
http://auto.howstuffworks.com/alternator2.htm to get a better idea of how
the workings go together with each other? It might be worth a read through,
to see if it gives any pointers on the connection layout and internal
workings.

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Default Excitation of 65 Kva Alternator

On 1 Nov, 15:19, George wrote:
I posted this on an Electrical Engineering Group, but no one knew
there, - does anyone know here ?


Try uk.rec.engines.stationary
Lots of generator people thereabouts
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Default Excitation of 65 Kva Alternator


"George" wrote in message
...
I posted this on an Electrical Engineering Group, but no one knew
there, - does anyone know here ?

I have had a very big 3 phase 415v 50 c/s alternator for years now
and
at last I need to put it into service.

It was manufactured by Mawdsley in the early 80s and when I shut it
down, I disconnected the AVR too and kept this and the spare I held.
I have checked with the Company and there is no way that they can
help
me with the excitation to fire it up. Before I go to all the trouble
of connecting it up to a diesel engine and spin it up to 1500 rpm,
can
anyone please tell me a few things about it.


It has a separate excitation generator on the end of the shaft and I
would imagine that this is still in circuit, as I have not been
inside
it yet. How does this set up actually work. does the alternator self
excite and the AVR just keep the output within narrow and automatic
limits? Will it produce 3 phase on it's own or is the AVR essential
and in this case is it a standard wiring circuit or will it be unique
to this alternator and AVR setup?


There is quite a lot of information on the makers plates on the two
units, but no information on how to connect it all up. The AVR
itself
has a whole lot of wire connections available but nothing to tell me
what goes where. I have spent hours looking for information on the
web, but with no luck.


Can you post some pictures somewhere. I know a lot about the theory but
nothing of the alternator you're describing.


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Default Excitation of 65 Kva Alternator

George wrote:

It was manufactured by Mawdsley in the early 80s and when I shut it
down, I disconnected the AVR too and kept this and the spare I held.
I have checked with the Company and there is no way that they can
help me with the excitation to fire it up.


Not even some documentation, connection diagrams, etc.?

Before I go to all the trouble of connecting it up to a diesel engine
and spin it up to 1500 rpm, can anyone please tell me a few things
about it.

[...]

How does this set up actually work.


Well it might or might not be something like the set I used to look
after a few years ago. This was of similar rating to yours (100 kVA)
and your description sounds somewhat familiar. AFAICR, 'mine' worked as
follows:

The electronic AVR, of which more later, provides a variable DC output
current to the stator (field) of the exciter machine - this will be the
"Exc. volts 16.5, amps 1.8" in your description.

The exciter's rotor produces a polyphase AC output which is immediately
rectified by diodes built into the combined rotor assemblies of the two
machines. The rectified output provides the DC excitation for the rotor
of the main alternator - this is is the "Excitation volts 71. amps 18"
in your description. It's an elegant arrangement since there are no
slip rings or brushes anywhere.

The main 3-phase AC output comes from the stator windings of the main
machine, which will be star-connected so as to provide a neutral point.

The AVR is essential to the operation of the whole set. It's a fairly
simple bit of circuitry, powered from one phase of the AC output via a
small mains transformer, bridge rectifier and reservoir capacitor. The
AC output voltage is sampled, rectified and compared to a Zener
reference, the difference being used to drive the exciter stator winding
via a switching power transistor (PWM control). A 'freewheel' diode
and the self inductance of the winding turn the hard-switched voltage
drive to the winding into a fairly steady DC excitation current.

A negative feedback loop is now in place - if the main AC output voltage
falls the AVR increases the exciter's stator current which increases the
output of the exciter which increases the rotor current in the main
alternator, thus tending to increase the AC output voltage. A pre-set
pot on the AVR module allows fine adjustment of the AC output voltage.

I hope this helps a little. For test purposes you could feed the
exciter stator from a car battery or an appropriately rated DC PSU.
Connect a shunt (reversed biased) diode firmly across the winding
terminals to prevent arcs, sparks and the risk of serious shocks and/or
insulation damage occurring when you disconnected the excitation.
Beware that, if you over-excite, the main output phase voltage may rise
to 300 V or more - enough to damage some loads (DAMHIKT).

It's also essential to observe correct polarity of the excitation
current and direction of rotation. The whole thing relies on residual
magnetism to boot itself up and you don't want to reverse this.

--
Andy


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Default Excitation of 65 Kva Alternator


"Andy Wade" wrote in message
...
George wrote:

It was manufactured by Mawdsley in the early 80s and when I shut it down,
I disconnected the AVR too and kept this and the spare I held. I have
checked with the Company and there is no way that they can help me with
the excitation to fire it up.


Not even some documentation, connection diagrams, etc.?

Before I go to all the trouble of connecting it up to a diesel engine
and spin it up to 1500 rpm, can anyone please tell me a few things
about it.

[...]

How does this set up actually work.


Well it might or might not be something like the set I used to look after
a few years ago. This was of similar rating to yours (100 kVA) and your
description sounds somewhat familiar. AFAICR, 'mine' worked as follows:

The electronic AVR, of which more later, provides a variable DC output
current to the stator (field) of the exciter machine - this will be the
"Exc. volts 16.5, amps 1.8" in your description.

The exciter's rotor produces a polyphase AC output which is immediately
rectified by diodes built into the combined rotor assemblies of the two
machines. The rectified output provides the DC excitation for the rotor
of the main alternator - this is is the "Excitation volts 71. amps 18" in
your description. It's an elegant arrangement since there are no slip
rings or brushes anywhere.

The main 3-phase AC output comes from the stator windings of the main
machine, which will be star-connected so as to provide a neutral point.

The AVR is essential to the operation of the whole set. It's a fairly
simple bit of circuitry, powered from one phase of the AC output via a
small mains transformer, bridge rectifier and reservoir capacitor. The AC
output voltage is sampled, rectified and compared to a Zener reference,
the difference being used to drive the exciter stator winding via a
switching power transistor (PWM control). A 'freewheel' diode and the
self inductance of the winding turn the hard-switched voltage drive to the
winding into a fairly steady DC excitation current.

A negative feedback loop is now in place - if the main AC output voltage
falls the AVR increases the exciter's stator current which increases the
output of the exciter which increases the rotor current in the main
alternator, thus tending to increase the AC output voltage. A pre-set pot
on the AVR module allows fine adjustment of the AC output voltage.

I hope this helps a little. For test purposes you could feed the exciter
stator from a car battery or an appropriately rated DC PSU. Connect a
shunt (reversed biased) diode firmly across the winding terminals to
prevent arcs, sparks and the risk of serious shocks and/or insulation
damage occurring when you disconnected the excitation. Beware that, if you
over-excite, the main output phase voltage may rise to 300 V or more -
enough to damage some loads (DAMHIKT).

It's also essential to observe correct polarity of the excitation current
and direction of rotation. The whole thing relies on residual magnetism
to boot itself up and you don't want to reverse this.


If the unit is as you say a brushless unit it's unlikely to be self exciting
and therefore unlikely that any residual magnetism will be sufficient to for
the rotor voltage to overcome the forward diode drops. If it's brushed then
it is more likely since brushes have very little forward drop.

I would have thought the AVR would have terminals for a battery for the
initial excitation? Given that this is a 1980's alternator I doubt the
electronics at the time would have stretched to supplying 71V and 18A. I
may well be wrong but I would have thought a mechanical vibrating regulator
would be more likely.


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Default Excitation of 65 Kva Alternator

On Nov 2, 12:57*pm, "Fred" wrote:
"Andy Wade" wrote in message

...



George wrote:


It was manufactured by Mawdsley in the early 80s and when I shut it down,
I disconnected the AVR too and kept this and the spare I held. I have
checked with the Company and there is no way that they can help me with
the excitation to fire it up.


Not even some documentation, connection diagrams, etc.?


Before I go to all the trouble of connecting it up to a diesel engine
and spin it up to 1500 rpm, can anyone please tell me a few things
about it.


[...]


How does this set up actually work.


Well it might or might not be something like the set I used to look after
a few years ago. *This was of similar rating to yours (100 kVA) and your
description sounds somewhat familiar. *AFAICR, 'mine' worked as follows:


The electronic AVR, of which more later, provides a variable DC output
current to the stator (field) of the exciter machine - this will be the
"Exc. volts 16.5, amps 1.8" in your description.


The exciter's rotor produces a polyphase AC output which is immediately
rectified by diodes built into the combined rotor assemblies of the two
machines. *The rectified output provides the DC excitation for the rotor
of the main alternator - this is is the "Excitation volts 71. amps 18" in
your description. *It's an elegant arrangement since there are no slip
rings or brushes anywhere.


The main 3-phase AC output comes from the stator windings of the main
machine, which will be star-connected so as to provide a neutral point.


The AVR is essential to the operation of the whole set. *It's a fairly
simple bit of circuitry, powered from one phase of the AC output via a
small mains transformer, bridge rectifier and reservoir capacitor. *The AC
output voltage is sampled, rectified and compared to a Zener reference,
the difference being used to drive the exciter stator winding via a
switching power transistor (PWM control). *A 'freewheel' diode and *the
self inductance of the winding turn the hard-switched voltage drive to the
winding into a fairly steady DC excitation current.


A negative feedback loop is now in place - if the main AC output voltage
falls the AVR increases the exciter's stator current which increases the
output of the exciter which increases the rotor current in the main
alternator, thus tending to increase the AC output voltage. *A pre-set pot
on the AVR module allows fine adjustment of the AC output voltage.


I hope this helps a little. *For test purposes you could feed the exciter
stator from a car battery or an appropriately rated DC PSU. Connect a
shunt (reversed biased) diode firmly across the winding terminals to
prevent arcs, sparks and the risk of serious shocks and/or insulation
damage occurring when you disconnected the excitation. Beware that, if you
over-excite, the main output phase voltage may rise to 300 V or more -
enough to damage some loads (DAMHIKT).


It's also essential to observe correct polarity of the excitation current
and direction of rotation. *The whole thing relies on residual magnetism
to boot itself up and you don't want to reverse this.


If the unit is as you say a brushless unit it's unlikely to be self exciting
and therefore unlikely that any residual magnetism will be sufficient to for
the rotor voltage to overcome the forward diode drops. *If it's brushed then
it is more likely since brushes have very little forward drop.

I would have thought the AVR would have terminals for a battery for the
initial excitation? *Given that this is a 1980's alternator I doubt the
electronics at the time would have stretched to supplying 71V and 18A. *I
may well be wrong but I would have thought a mechanical vibrating regulator
would be more likely.


That sounds more like a description of 1950s kit. 1980s electronic
power supplies went up to 100s of 1000s of volts and hundreds of amps.


I dont know the specific gen set, but the following setup is a classic
arrangement, and probably what you've got:

The small machine is a permanent magnet generator. This produces a low
power output which is used to excite the main machine. The latter
produces high power, and its V_out is regulated by adjusting the
exictation voltage. Since this is a modern gen it'll all be done
automatically and electronically.

Such a 2 machine set doesn't rely on residual magnetism at any time.

You can test the main gen's output safely by using a very low
excitation voltage, such as a 1.5v D cell, which will give you
somewhere vaguely in the region of 5v on the mains output terminals.
5v 90A from an inductive source should not be disrespected too much,
its still capable of turning metal red, fire or possibly fatal shock
(due to inductive kickback).

The electronic regulator will likely not tolerate any nonsense, so it
must be wired up correctly first time to avoid releasing any smoke.
The inital run can be done at much reduced speed to check the basic
function is ok, though expect the voltage regulation to malfunction at
low speed. Since you've got electronics in there, and probably
unprotected electronics, do _not_ just spin it up and connect wires
any which way to see what works.


NT
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Default Excitation of 65 Kva Alternator

Fred wrote:

I would have thought the AVR would have terminals for a battery for the
initial excitation? Given that this is a 1980's alternator I doubt the
electronics at the time would have stretched to supplying 71V and 18A. I
may well be wrong but I would have thought a mechanical vibrating regulator
would be more likely.

Back in the 1980s we had these things called "computers" which were
sometimes the size of a small car, and ate 10s of kW at 5V. And we had
these other things called "Radars" which sometimes ate megawatts - at a
somewhat higher voltage.

So I wouldn't be at all surprised to find an electronic one in equipment
of that vintage.

Andy
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"Andy Champ" wrote in message
. uk...
Fred wrote:

I would have thought the AVR would have terminals for a battery for the
initial excitation? Given that this is a 1980's alternator I doubt the
electronics at the time would have stretched to supplying 71V and 18A. I
may well be wrong but I would have thought a mechanical vibrating
regulator would be more likely.

Back in the 1980s we had these things called "computers" which were
sometimes the size of a small car, and ate 10s of kW at 5V. And we had
these other things called "Radars" which sometimes ate megawatts - at a
somewhat higher voltage.

So I wouldn't be at all surprised to find an electronic one in equipment
of that vintage.

Andy


I said I might be wrong. I think you'll find the cost of a radar or even a
sensible computer in the early 80's probably cost more than this generator.

Until recently the regulator in your car dashboard was a vibrating reed
affair. It worked, was cheaper and more rugged to abuse than semiconductor
equivalents. Similarly flasher relays. The access of new technology
doesn't mean it's immediately a cost effective solution to every engineering
problem.


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Default Excitation of 65 Kva Alternator

We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember "Fred" saying
something like:

I would have thought the AVR would have terminals for a battery for the
initial excitation? Given that this is a 1980's alternator I doubt the
electronics at the time would have stretched to supplying 71V and 18A. I
may well be wrong but I would have thought a mechanical vibrating regulator
would be more likely.


I was building those into gensets in the early 80s, and yes, they were
self-exciting. Mechanical vibrators are so 50s, daddy-oh.


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Fred wrote:

I think you'll find the cost of a radar or even a
sensible computer in the early 80's probably cost more than this generator.

I'll give you that!

Until recently the regulator in your car dashboard was a vibrating reed
affair. It worked, was cheaper and more rugged to abuse than semiconductor
equivalents. Similarly flasher relays. The access of new technology
doesn't mean it's immediately a cost effective solution to every engineering
problem.


Can't say for sure. I only know about the bits that went wrong(and
there were enough of those!). But in this case, I'll defer to the GC.

Andy
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Fred wrote:

If the unit is as you say a brushless unit it's unlikely to be self exciting
and therefore unlikely that any residual magnetism will be sufficient to for
the rotor voltage to overcome the forward diode drops. If it's brushed then
it is more likely since brushes have very little forward drop.


The one I looked after was definitely self-excited. The only battery
involved was for the engine starter motor.

I would have thought the AVR would have terminals for a battery for the
initial excitation? Given that this is a 1980's alternator I doubt the
electronics at the time would have stretched to supplying 71V and 18A.


Did you read my description properly? That level of voltage and current
are for the main alternator and the only 'electronics' involved is the
rectifier diodes built into the rotor. The PWM o/p from the AVR was in
the same 16 V, 1.8 A range mentioned by the OP, and was handled by a
single TO3 power transistor - possibly an OC35(!) although I can't
remember for sure.

--
Andy
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On 3 Nov, 23:31, Andy Wade wrote:
Fred wrote:
If the unit is as you say a brushless unit it's unlikely to be self exciting
and therefore unlikely that any residual magnetism will be sufficient to for
the rotor voltage to overcome the forward diode drops. *If it's brushed then
it is more likely since brushes have very little forward drop.


The one I looked after was definitely self-excited. *The only battery
involved was for the engine starter motor.

I would have thought the AVR would have terminals for a battery for the
initial excitation? *Given that this is a 1980's alternator I doubt the
electronics at the time would have stretched to supplying 71V and 18A.


Did you read my description properly? *That level of voltage and current
are for the main alternator and the only 'electronics' involved is the
rectifier diodes built into the rotor. *The PWM o/p from the AVR was in
the same 16 V, 1.8 A range mentioned by the OP, and was handled by a
single TO3 power transistor - possibly an OC35(!) although I can't
remember for sure.

--
Andy


Hi there,

In fact I was not expecting so much information, having searched all
over for several months. I posted first in alt.electrical engineering.
I have not been back there either as I was disappointed by the lack of
interest.

Having read all these posts I am very motivated now. However this is a
big machine and I was planning to build it all on two heavy bits of
channel and make up the drive coupling to one of two Perkins P3
engines I have - or even sacrifice the 1.9 litre engine out of an old
Mondeo I am still using, but which has a limited expected life. This
is pretty efficient and most of all, - quiet, at this sort of speed.
However it is not something I can just Hook Up. I wanted to be fairly
sure that it could be made to work and was very disappointed when
Mawdsley told me that they had ditched all their historical data
during past reorganisations.

The technology is actually 1970,s but it is way ahead of the old car
regulator. I shall remove the covers to the exciter and take some
pictures. but it will take a few days. Watch this space. The
alternator was driven in line by a similar sized 3 phase motor
continuously, to provide a smooth supply to a medium sized ICL
computer installation. A Quick Start diesel Generator came up in a few
seconds in the event of a complete mains failure, but this set could
spin on with little drop in speed for this time. There was a lot of
rotating mass. It certainly worked, but the next generation was a big
UPS. Although I was the resident ICL Rep. I was the only one with
any technical training and so everything of this nature fell in my lap
by default. Even the old equipment that was taken out!

My sincere thanks to those who have helped, it has given me a whole
lot to investigate and the will to get started.

Many thanks, George Bell.



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In article 2b84c553-6efb-4f1e-bce0-f53f9ff5acd7
@a3g2000prm.googlegroups.com, says...

In fact I was not expecting so much information, having searched all
over for several months. I posted first in alt.electrical engineering.
I have not been back there either as I was disappointed by the lack of
interest.

Having read all these posts I am very motivated now. However this is a
big machine and I was planning to build it all on two heavy bits of
channel and make up the drive coupling to one of two Perkins P3
engines I have - or even sacrifice the 1.9 litre engine out of an old
Mondeo I am still using, but which has a limited expected life. This
is pretty efficient and most of all, - quiet, at this sort of speed.
However it is not something I can just Hook Up. I wanted to be fairly
sure that it could be made to work and was very disappointed when
Mawdsley told me that they had ditched all their historical data
during past reorganisations.

The technology is actually 1970,s but it is way ahead of the old car
regulator. I shall remove the covers to the exciter and take some
pictures. but it will take a few days. Watch this space. The
alternator was driven in line by a similar sized 3 phase motor
continuously, to provide a smooth supply to a medium sized ICL
computer installation. A Quick Start diesel Generator came up in a few
seconds in the event of a complete mains failure, but this set could
spin on with little drop in speed for this time. There was a lot of
rotating mass. It certainly worked, but the next generation was a big
UPS. Although I was the resident ICL Rep. I was the only one with
any technical training and so everything of this nature fell in my lap
by default. Even the old equipment that was taken out!


Ah the nostalgia... Storing loads of energy in flywheels to cover the
start-up time of diesel generators - and trying to get it runnning in
the first place. Loads of switchery...

Reminds me of when, as a DEC product support engineer, I was asked if
our computer would run on the same motor generator set as the ICL it was
replacing. The reply was that it would and, what's more, would fit in
the corner of the same room :-) The customer desided to accept our
recommendation for a new SS UPS which lived in the corner of the large,
almost empty, computer room

--
John W
To mail me replace the obvious with co.uk twice
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On 4 Nov, 12:24, John Weston wrote:
In article ,
says...



Ah the nostalgia... Storing loads of energy in flywheels to cover the
start-up time of diesel generators - and trying to get it runnning in
the first place. Loads of switchery...


Reminds me of when, as a DEC product support engineer, I was asked if
our computer would run on the same motor generator set as the ICL it was
replacing. *The reply was that it would and, what's more, would fit in
the corner of the same room :-) *The customer desided to accept our
recommendation for a new SS UPS which lived in the corner of the large,
almost empty, computer room


desided - who wrote that?

--
John W
To mail me replace the obvious with co.uk twice


Little gremlins do that, their favourite toys are typos.

I got my trusty tractor out today and moved 7 layers of "useful"
things and finally got to the alternator, which of course was at the
back.

Why can't I copy and paste a picture??? I shall make a page on my
website when I get a few more. This is no problem now I have it out in
the open. I took the cover off the exciter and there were a bunch of
rotating rectifiers and when I took off the cover where all the cables
come out there were 3 fat phases and a neutral and two obvious
excitation wires labelled x and xx. I don't think there will be a
problem sorting out which is which. 6 wires in all, - what could be
simpler?

It's quite clean inside but I shall high pressure water it and then
wire brush and paint the outside. I looked at my scrap pile, but I
only have one length of big channel. I'll get another. I think this
is going to be easier than I first thought. I do have a long railway
sleeper which I could cut in half and mount the alt. and an engine on
that. I think I prefer a good solid chunk of steel.

More later. Regards George.
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We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember George
saying something like:

Having read all these posts I am very motivated now. However this is a
big machine and I was planning to build it all on two heavy bits of
channel and make up the drive coupling to one of two Perkins P3
engines I have - or even sacrifice the 1.9 litre engine out of an old
Mondeo I am still using, but which has a limited expected life. This
is pretty efficient and most of all, - quiet, at this sort of speed.



What's the rated speed of the alternator?

3000rpm - you're laughing for direct drive.

If it's 1500rpm, you'll find a car engine with a road camshaft to be
right on the edge of its torque curve if you pull any real power out of
that set at low speeds if it's direct coupled.
I'd look at an HD pulley drive to bring the engine speed up to ~2000rpm
if possible.

If the speed is 750 rpm, forget direct coupling entirely.
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On 5 Nov, 00:41, Grimly Curmudgeon
wrote:
We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember George
saying something like:

Having read all these posts I am very motivated now. However this is a
big machine and I was planning to build it all on two heavy bits of
channel and make up the drive coupling to one of two Perkins P3
engines I have - or even sacrifice the 1.9 litre engine out of an old
Mondeo I am still using, but which has a limited expected life. *This
is pretty efficient and most of all, - quiet, at this sort of speed.


What's the rated speed of the alternator?

3000rpm - you're laughing for direct drive.

If it's 1500rpm, you'll find a car engine with a road camshaft to be
right on the edge of its torque curve if you pull any real power out of
that set at low speeds if it's direct coupled.
I'd look at an HD pulley drive to bring the engine speed up to ~2000rpm
if possible.

If the speed is 750 rpm, forget direct coupling entirely.


Thanks for that. It is 1500. rpm. But I am only going to try and use
this 65 Kva alternator because I have it. The only other one I have
is about 5Kva and not strong enough to drive the 3 main motors I have
in my workshop, currently a Herbert Lathe 5 or 7 1/2 HP . A Denbigh
Mill and a low HP pillar drill. I am also thinking of a big welding,
- plasma cutter set. Second hand 3 phase is cheaper as not so many
people have it.

My worst load is the Herbert and I am still able to get it up to speed
if I wait a bit, on a cold morning, using a 3HP. 1 to 3 phase
converter. The sheer weight of the alternator rotating parts will
give a nice start-up capability. I am not all that concerned about
exact frequency stability. A pretty simple AVR will also suffice. In
the future I may use it to charge up inverter batteries for a combined
heat and power set up, running on bio-diesel. It will be neater to
directly couple it so I would prefer to run at 1500. It will go in an
insulated space and so not annoy neighbours, the water being plumbed
in to a hot water tank and central heating. Waste not, want not. I
shall only start it up when I need it.

What do you think?

Regards George.

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Default Excitation of 65 Kva Alternator

Having read all these posts I am very motivated now. However this is a
big machine and I was planning to build it all on two heavy bits of
channel and make up the drive coupling to one of two Perkins P3
engines I have - or even sacrifice the 1.9 litre engine out of an old
Mondeo I am still using, but which has a limited expected life. *This
is pretty efficient and most of all, - quiet, at this sort of speed.


What's the rated speed of the alternator?

3000rpm - you're laughing for direct drive.

If it's 1500rpm, you'll find a car engine with a road camshaft to be
right on the edge of its torque curve if you pull any real power out of
that set at low speeds if it's direct coupled.
I'd look at an HD pulley drive to bring the engine speed up to ~2000rpm
if possible.

If the speed is 750 rpm, forget direct coupling entirely.


Thanks for that. It is 1500. rpm. But I am only going to try and use
this 65 Kva alternator because I have it. The only other one I have
is about 5Kva and not strong enough to drive the 3 main motors I have
in my workshop, currently a Herbert Lathe 5 or 7 1/2 HP . A Denbigh
Mill and a low HP pillar drill. I am also thinking of a big welding,
- plasma cutter set. Second hand 3 phase is cheaper as not so many
people have it.

My worst load is the Herbert and I am still able to get it up to speed
if I wait a bit, on a cold morning, using a 3HP. 1 to 3 phase
converter. The sheer weight of the alternator rotating parts will
give a nice start-up capability. I am not all that concerned about
exact frequency stability. A pretty simple AVR will also suffice. In
the future I may use it to charge up inverter batteries for a combined
heat and power set up, running on bio-diesel. It will be neater to
directly couple it so I would prefer to run at 1500. It will go in an
insulated space and so not annoy neighbours, the water being plumbed
in to a hot water tank and central heating. Waste not, want not. I
shall only start it up when I need it.

What do you think?

Regards George.


Set up a project website so we can see the Gennie's progress:-))...
--
Tony Sayer


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On Wed, 5 Nov 2008 08:14:50 +0000, tony sayer wrote:


In the future I may use it to charge up inverter batteries for a
combined heat and power set up, running on bio-diesel. It will be
neater to directly couple it so I would prefer to run at 1500.


And easier to find a diesel engine with useable grunt at 1500 rpm.

the water being plumbed in to a hot water tank and central heating.
Waste not, want not.


Diesels are much more thermodynamicly effcient than petrols and don't
produce much waste heat unless they are being asked to work. But as you
say waste not want not.

Set up a project website so we can see the Gennie's progress:-))...


Yeah, an interesting project.

--
Cheers
Dave.





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On Nov 5, 6:48*am, George wrote:
On 5 Nov, 00:41, Grimly Curmudgeon
wrote:



We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember George
saying something like:


Having read all these posts I am very motivated now. However this is a
big machine and I was planning to build it all on two heavy bits of
channel and make up the drive coupling to one of two Perkins P3
engines I have - or even sacrifice the 1.9 litre engine out of an old
Mondeo I am still using, but which has a limited expected life. *This
is pretty efficient and most of all, - quiet, at this sort of speed.


What's the rated speed of the alternator?


3000rpm - you're laughing for direct drive.


If it's 1500rpm, you'll find a car engine with a road camshaft to be
right on the edge of its torque curve if you pull any real power out of
that set at low speeds if it's direct coupled.
I'd look at an HD pulley drive to bring the engine speed up to ~2000rpm
if possible.


If the speed is 750 rpm, forget direct coupling entirely.


Thanks for that. *It is 1500. rpm. *But I am only going to try and use
this 65 Kva alternator because I have it. *The only other one I have
is about 5Kva and not strong enough to drive the 3 main motors I have
in my workshop, currently a Herbert Lathe *5 or 7 1/2 HP . A Denbigh
Mill and a low HP pillar drill. *I am also thinking of a big welding,
- plasma cutter set. Second hand 3 phase is cheaper as not so many
people have it.

My worst load is the Herbert and I am still able to get it up to speed
if I wait a bit, on a cold morning, using a 3HP. *1 to 3 phase
converter. * *The sheer weight of the alternator rotating parts will
give a nice start-up capability. *I am not all that concerned about
exact frequency stability. *A pretty simple AVR will also suffice. *In
the future I may use it to charge up inverter batteries for a combined
heat and power set up, running on bio-diesel. *It will be neater to
directly couple it so I would prefer to run at 1500. *It will go in an
insulated space and so not annoy neighbours, the water being plumbed
in to a hot water tank and central heating. *Waste not, want not. I
shall only start it up when I need it.

What do you think?

Regards George.


There sholdnt be anything preventing you from getting it rnning, as
long as it works. With 3 machine shop tools on a 65kva gen you wont
need regulation, so even if the reg & exciter were toasted you could
run the main machine's field off an unregged supply such as a car
alternator (with its regulation removed).


NT
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On Nov 4, 7:01*am, George wrote:
On 3 Nov, 23:31, Andy Wade wrote:



Fred wrote:
If the unit is as you say a brushless unit it's unlikely to be self exciting
and therefore unlikely that any residual magnetism will be sufficient to for
the rotor voltage to overcome the forward diode drops. *If it's brushed then
it is more likely since brushes have very little forward drop.


The one I looked after was definitely self-excited. *The only battery
involved was for the engine starter motor.


I would have thought the AVR would have terminals for a battery for the
initial excitation? *Given that this is a 1980's alternator I doubt the
electronics at the time would have stretched to supplying 71V and 18A..


Did you read my description properly? *That level of voltage and current
are for the main alternator and the only 'electronics' involved is the
rectifier diodes built into the rotor. *The PWM o/p from the AVR was in
the same 16 V, 1.8 A range mentioned by the OP, and was handled by a
single TO3 power transistor - possibly an OC35(!) although I can't
remember for sure.


--
Andy


Hi there,

In fact I was not expecting so much information, having searched all
over for several months. I posted first in alt.electrical engineering.
I have not been back there either as I was disappointed by the lack of
interest.

Having read all these posts I am very motivated now. However this is a
big machine and I was planning to build it all on two heavy bits of
channel and make up the drive coupling to one of two Perkins P3
engines I have - or even sacrifice the 1.9 litre engine out of an old
Mondeo I am still using, but which has a limited expected life. *This
is pretty efficient and most of all, - quiet, at this sort of speed.
However it is not something I can just Hook Up. I wanted to be fairly
sure that it could be made to work and was very disappointed when
Mawdsley told me that they had ditched all their historical data
during past reorganisations.

The technology is actually 1970,s but it is way ahead of the old car
regulator. *I shall remove the covers to the exciter and take some
pictures. *but it will take a few days. *Watch this space. *The
alternator was driven in line by a similar sized 3 phase motor
continuously, to provide a smooth supply to a medium sized ICL
computer installation. A Quick Start diesel Generator came up in a few
seconds in the event of a complete mains failure, but this set could
spin on with little drop in speed for this time. There was a lot of
rotating mass. *It certainly worked, but the next generation was a big
UPS. * *Although I was the resident ICL Rep. I was the only one with
any technical training and so everything of this nature fell in my lap
by default. *Even the old equipment that was taken out!

My sincere thanks to those who have helped, it has given me a whole
lot to investigate and the will to get started.

Many thanks, George Bell.


As long as the main gen has continuity on its windings and the
bearings work, it should be perfectly runnable. Even if the rest of
the kit were toast you could run the main machine off a fixed
excitation voltage, as theres no way you'd need regulation to run 3
motors off a 65kva genset. So I wouldnt let the worries about the
regulator etc stop you building it.


NT
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On 5 Nov, 06:48, George wrote:
On 5 Nov, 00:41, Grimly Curmudgeon
wrote:





We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember George
saying something like:


Having read all these posts I am very motivated now. However this is a
big machine and I was planning to build it all on two heavy bits of
channel and make up the drive coupling to one of two Perkins P3
engines I have - or even sacrifice the 1.9 litre engine out of an old
Mondeo I am still using, but which has a limited expected life. *This
is pretty efficient and most of all, - quiet, at this sort of speed.


What's the rated speed of the alternator?


3000rpm - you're laughing for direct drive.


If it's 1500rpm, you'll find a car engine with a road camshaft to be
right on the edge of its torque curve if you pull any real power out of
that set at low speeds if it's direct coupled.
I'd look at an HD pulley drive to bring the engine speed up to ~2000rpm
if possible.


If the speed is 750 rpm, forget direct coupling entirely.


Thanks for that. *It is 1500. rpm. *But I am only going to try and use
this 65 Kva alternator because I have it. *The only other one I have
is about 5Kva and not strong enough to drive the 3 main motors I have
in my workshop, currently a Herbert Lathe *5 or 7 1/2 HP . A Denbigh
Mill and a low HP pillar drill. *I am also thinking of a big welding,
- plasma cutter set. Second hand 3 phase is cheaper as not so many
people have it.

My worst load is the Herbert and I am still able to get it up to speed
if I wait a bit, on a cold morning, using a 3HP. *1 to 3 phase
converter. * *The sheer weight of the alternator rotating parts will
give a nice start-up capability. *I am not all that concerned about
exact frequency stability. *A pretty simple AVR will also suffice. *In
the future I may use it to charge up inverter batteries for a combined
heat and power set up, running on bio-diesel. *It will be neater to
directly couple it so I would prefer to run at 1500. *It will go in an
insulated space and so not annoy neighbours, the water being plumbed
in to a hot water tank and central heating. *Waste not, want not. I
shall only start it up when I need it.

What do you think?

Regards George.- Hide quoted text -

- Show quoted text -


I have put a few pictures on my website showing how dirty it is at the
moment and the excitation details - as far as I can see.

http://maribelecosystems.com/OldEngines.html
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On Nov 5, 1:40*pm, George wrote:
On 5 Nov, 06:48, George wrote:



On 5 Nov, 00:41, Grimly Curmudgeon
wrote:


We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember George
saying something like:


Having read all these posts I am very motivated now. However this is a
big machine and I was planning to build it all on two heavy bits of
channel and make up the drive coupling to one of two Perkins P3
engines I have - or even sacrifice the 1.9 litre engine out of an old
Mondeo I am still using, but which has a limited expected life. *This
is pretty efficient and most of all, - quiet, at this sort of speed.


What's the rated speed of the alternator?


3000rpm - you're laughing for direct drive.


If it's 1500rpm, you'll find a car engine with a road camshaft to be
right on the edge of its torque curve if you pull any real power out of
that set at low speeds if it's direct coupled.
I'd look at an HD pulley drive to bring the engine speed up to ~2000rpm
if possible.


If the speed is 750 rpm, forget direct coupling entirely.


Thanks for that. *It is 1500. rpm. *But I am only going to try and use
this 65 Kva alternator because I have it. *The only other one I have
is about 5Kva and not strong enough to drive the 3 main motors I have
in my workshop, currently a Herbert Lathe *5 or 7 1/2 HP . A Denbigh
Mill and a low HP pillar drill. *I am also thinking of a big welding,
- plasma cutter set. Second hand 3 phase is cheaper as not so many
people have it.


My worst load is the Herbert and I am still able to get it up to speed
if I wait a bit, on a cold morning, using a 3HP. *1 to 3 phase
converter. * *The sheer weight of the alternator rotating parts will
give a nice start-up capability. *I am not all that concerned about
exact frequency stability. *A pretty simple AVR will also suffice. *In
the future I may use it to charge up inverter batteries for a combined
heat and power set up, running on bio-diesel. *It will be neater to
directly couple it so I would prefer to run at 1500. *It will go in an
insulated space and so not annoy neighbours, the water being plumbed
in to a hot water tank and central heating. *Waste not, want not. I
shall only start it up when I need it.


What do you think?


Regards George.- Hide quoted text -


- Show quoted text -


I have put a few pictures on my website showing how dirty it is at the
moment and the excitation details - as far as I can see.

http://maribelecosystems.com/OldEngines.html


re the AVR...
how many external connections does it have?
the big capacitor is most likiely on the input from the small gen.

With your skill & experience plus some help on the electrics this
should be entirely doable.


NT
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On Wed, 5 Nov 2008 05:40:28 -0800 (PST), George wrote:

I have put a few pictures on my website showing how dirty it is at the
moment and the excitation details - as far as I can see.

http://maribelecosystems.com/OldEngines.html


Very enjoyable read about the engines - thanks.

Geo


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George wrote:

The technology is actually 1970,s but it is way ahead of the old car
regulator. I shall remove the covers to the exciter and take some
pictures. but it will take a few days. Watch this space. The
alternator was driven in line by a similar sized 3 phase motor
continuously, to provide a smooth supply to a medium sized ICL
computer installation.



That rings a bell. We had such a setup in the machine room at BRA01 to
drive the 2980. It never worked though, and you wouldn't call a 2980
"medium sized" either. One of those little things - I knew it was
there, but never actually saw it, just heard it cursed!

Andy
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On Wed, 5 Nov 2008 20:11:02 UTC, Andy Champ wrote:

That rings a bell. We had such a setup in the machine room at BRA01 to
drive the 2980. It never worked though, and you wouldn't call a 2980
"medium sized" either. One of those little things - I knew it was
there, but never actually saw it, just heard it cursed!


We had one too. In fact, when I last looked we still had it. It was
installed in 1976 to drive a an ICL 2960 installation (ICL insisted we
had it). It was installed in an outbuilding, and just ran...and
ran...and ran. It then ran our VAXcluster ten years later, and if it's
not still there, it hasn't been gone for all that long.

I remember ICL diddled us (mainly incompetence, which was the norm for
them). After six years someone noticed this thing hadn't been serviced,
but ICL had been charging us a large sum over the years for its
maintenance. I think we got the money back and took out a contract with
the manufacturers.

One of the most amazingly reliable pieces of kit I have ever seen. It
ran for six years without stopping, and then for a year at a time
between maintenance checks. It was from Mawdsley, I'm pretty sure.

ICL were the bane of my life for ten years...don't even get me onto the
CPU hardware design flaw they refused to fix, which involved me writing
microcode patches...

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We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember George
saying something like:

Thanks for that. It is 1500. rpm. But I am only going to try and use
this 65 Kva alternator because I have it. The only other one I have
is about 5Kva and not strong enough to drive the 3 main motors I have
in my workshop, currently a Herbert Lathe 5 or 7 1/2 HP . A Denbigh
Mill and a low HP pillar drill. I am also thinking of a big welding,
- plasma cutter set. Second hand 3 phase is cheaper as not so many
people have it.


Excellent idea, and one I'm pursuing, trying to find a big 3ph
alternator cheaply locally, as the carriage costs for such a thing are
horrendous. I too have noticed the dirt cheap prices of 3ph kit.


My worst load is the Herbert and I am still able to get it up to speed
if I wait a bit, on a cold morning, using a 3HP. 1 to 3 phase
converter. The sheer weight of the alternator rotating parts will
give a nice start-up capability. I am not all that concerned about
exact frequency stability. A pretty simple AVR will also suffice. In
the future I may use it to charge up inverter batteries for a combined
heat and power set up, running on bio-diesel. It will be neater to
directly couple it so I would prefer to run at 1500. It will go in an
insulated space and so not annoy neighbours, the water being plumbed
in to a hot water tank and central heating. Waste not, want not. I
shall only start it up when I need it.

What do you think?


The CHP setup is the way to go, for sure.

Regarding the engines, the P3 is only 2.3L, which in itself isn't a real
problem, as you won't be pulling out anywhere near the max capacity of
the alternator, but I can't find any figures for the P3 itself. I can
only guess at its output at 1500rpm from my looking into using a VW 2L
road diesel engine for the same purpose. At 1500rpm the VW engine is
producing 100Nm of torque, compared to its peak of 102Nm just 500rpm
higher - in this it's fairly characteristic of diesels, producing a lot
of low down grunt and rapidly running out of steam above that. The power
curve is disappointing for this purpose - at 1500rpm it's only producing
~15kW, rising to ~40kW @4800rpm.
This is why I mentioned the camshaft above - the same engine produced by
VW for stationary power has a different camshaft (indeed, as do all of
them) for plant applications, maximising the breathing for the steady
speed they will be doing.

Anyway, it's like comparing apples and oranges - the P3 is an ancient
design and will probably be less good than the VW, but it's a stationary
engine, so you might be in with a shout and who knows, it might produce
more power at 1500 rpm than the VW.

Regarding the direct coupling - don't fack about, go to a decent power
transmission stockist and tell them what you're up to and what they
recommend. There's a range of couplings you could use and a range of
prices too, but you need to get it right. Fecking dangerous if you
don't.
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On Thu, 06 Nov 2008 08:45:39 +0000, The Natural Philosopher wrote:

Heating oil, kersosene, parafin, (28sec oil) for domestic heating has
no duty and VAT is at 5%


So how come its 45p/liter ten?


Mostly the base cost of the oil. With road fuel duty at 50p/l (ish) and
VAT at 17.5% heating oil should be below 40p/l.

Just checked one of my regular online quote places and they come out at
43.08 and I can normally beat them by 2p/l locally. That site came out
41.06 on the 24th Oct. It's not a simple relationship from crude to retail
price, availabilty and demand affect it as well. It's just been cold and
winter is approaching so I suspect demand is quite high, this tends to
push the price up a few p/l.

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On 6 Nov, 07:59, "Dave Liquorice"
wrote:

You can claim back the duty you pay on petrol if you jump through the
right hoops with HMR&C.


Really? Last time I dealt with this (vintage tractors) the whole non-
road petrol supply chain was being withdrawn owing to lack of demand
(and potential for abuse). You must (AFAIK) pay duty on fuel _unless_
it's dyed to make it traceable, and dyed petrol was going out of
production.
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On Thu, 6 Nov 2008 03:57:00 -0800 (PST), Andy Dingley wrote:

You can claim back the duty you pay on petrol if you jump through the
right hoops with HMR&C.


Really? Last time I dealt with this (vintage tractors) the whole non-
road petrol supply chain was being withdrawn owing to lack of demand
(and potential for abuse). You must (AFAIK) pay duty on fuel _unless_
it's dyed to make it traceable, and dyed petrol was going out of
production.


I dug about on the HMR&C website and got the impression it was a paper
exercise but I can see where you are coming from with dyes etc. Note I
said "claim back" as opposed to not paying it in the first place.

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Dave.



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We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember Andy Dingley
saying something like:


You can claim back the duty you pay on petrol if you jump through the
right hoops with HMR&C.


Really? Last time I dealt with this (vintage tractors) the whole non-
road petrol supply chain was being withdrawn owing to lack of demand
(and potential for abuse). You must (AFAIK) pay duty on fuel _unless_
it's dyed to make it traceable, and dyed petrol was going out of
production.


Aviation spirit used be blue, iirc, and I don't see that going out of
production. [1] There's certainly a mechanism in place for reclaiming
duty paid on that if you're going abroad with it - I would think there
would still be a demand for that, and it's essentially the same
procedure.

[1] My Minivan ran great on it.
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On Thu, 06 Nov 2008 14:35:11 +0000, Grimly Curmudgeon wrote:

We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember Andy Dingley
saying something like:


You can claim back the duty you pay on petrol if you jump through the
right hoops with HMR&C.


Really? Last time I dealt with this (vintage tractors) the whole non-
road petrol supply chain was being withdrawn owing to lack of demand
(and potential for abuse). You must (AFAIK) pay duty on fuel _unless_
it's dyed to make it traceable, and dyed petrol was going out of
production.


Aviation spirit used be blue, iirc, and I don't see that going out of
production. [1] There's certainly a mechanism in place for reclaiming
duty paid on that if you're going abroad with it - I would think there
would still be a demand for that, and it's essentially the same
procedure.

[1] My Minivan ran great on it.


Hi all,

As a user of AVGAS (100/110 octane low leaded version) it is blue and
smells wonderful 8-))

There is duty & VAT on it and currently it is anywhere from 146p/l to
170 p/l PLUS VAT. However it is rumoured to be on the way out as the
lead contaminates the plant and so noone wants to make it as it needs a
dedicated bit of kit and is a 'small' market - hence the price!

The Swedish (I think) have got unleaded AVGAS that performs like
100/110LL (I am told) but there is no duty relief on it and is likely to
be more expensive.

And yes you can claw back duty if you 'export' it across the channel (or
as I do here just not pay it in the first place - AirBP have a system)

The Nomad


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On 6 Nov, 17:12, The Nomad wrote:
On Thu, 06 Nov 2008 14:35:11 +0000, Grimly Curmudgeon wrote:
We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember Andy Dingley
saying something like:


You can claim back the duty you pay on petrol if you jump through the
right hoops with HMR&C.


Really? *Last time I dealt with this (vintage tractors) the whole non-
road petrol supply chain was being withdrawn owing to lack of demand
(and potential for abuse). You must (AFAIK) pay duty on fuel _unless_
it's dyed to make it traceable, and dyed petrol was going out of
production.


Aviation spirit used be blue, iirc, and I don't see that going out of
production. [1] There's certainly a mechanism in place for reclaiming
duty paid on that if you're going abroad with it - I would think there
would still be a demand for that, and it's essentially the same
procedure.


[1] My Minivan ran great on it.


Hi all,

As a user of AVGAS (100/110 octane low leaded version) it is blue and
smells wonderful 8-))

There is duty *& VAT on it and currently it is anywhere from 146p/l to
170 p/l PLUS VAT. *However it is rumoured to be on the way out as the
lead contaminates the plant and so noone wants to make it as it needs a
dedicated bit of kit and is a 'small' market - hence the price!

The Swedish (I think) have got unleaded AVGAS that performs like
100/110LL (I am told) but there is no duty relief on it and is likely to
be more expensive.

And yes you can claw back duty if you 'export' it across the channel (or
as I do here just not pay it in the first place - AirBP have a system)

The Nomad- Hide quoted text -

- Show quoted text -


When I was on Shackletons AVGAS was 130/135 Octane and although it ran
very well in my Triumph T 110. It was reputed to burn out valves. It
did not effect mine so as far as I was concerned it was perfect and
very cost effective.

But I digress. I have just found that the Perkins P3 has a power of
34 hp / 1500 rpm. As it is quoted at this rpm it may well be that
this is the rpm at which it is happy. Today I found two 8 ft. pieces
of very heavy, - not channel, but I section which will be just as good
as there is plenty of room for nice fat bolts. I am in the process of
painting it a nice tasteful British Racing Green. 1 shop I have found
in Norwich has AVRs which can be adapted to any (?) alternator. The
only problem is that it is 40 quid. OUCH. Anyone got a simple
circuit?

Regards George.



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