Ive got a 5hp PC3 vfd running my Gorton MasterMill.
The top end voltage it is supposed to run on..is 230vts + about 5 volts
It will run down to 200 volts.
Im running it on single phase, been doing it for years.

Now the power company has increased my 220 single phase to about 249
volts and when I try to start it..I keep getting OverVoltage Alarm.

I cant get the power company to change the tap down to a normal voltage,
let alone 220 volts

How do I (cheaply) transform high voltage down 14-29 volts ac?

Id hate to loose the VFD on this mill and have to run it off a RPC
(which also puts out higher voltages)

Gunner

--
"If I say two plus two is four and a Democrat says two plus two is eight,
it's not a partial victory for me when we agree that two plus two is
six. " Jonah Goldberg (modified)

Gunner Asch wrote:

Ive got a 5hp PC3 vfd running my Gorton MasterMill.
The top end voltage it is supposed to run on..is 230vts + about 5 volts
It will run down to 200 volts.
Im running it on single phase, been doing it for years.

Now the power company has increased my 220 single phase to about 249
volts and when I try to start it..I keep getting OverVoltage Alarm.

I cant get the power company to change the tap down to a normal voltage,
let alone 220 volts

How do I (cheaply) transform high voltage down 14-29 volts ac?

Id hate to loose the VFD on this mill and have to run it off a RPC
(which also puts out higher voltages)


How much current do you need? A simple buck transformer will do the
job, as long as it's secondary can handle the current.


--
You can't fix stupid. You can't even put a Band-Aid™ on it, because it's
Teflon coated.

"Gunner Asch" wrote in message
...
Ive got a 5hp PC3 vfd running my Gorton MasterMill.
The top end voltage it is supposed to run on..is 230vts + about 5 volts
It will run down to 200 volts.
Im running it on single phase, been doing it for years.

Now the power company has increased my 220 single phase to about 249
volts and when I try to start it..I keep getting OverVoltage Alarm.

I cant get the power company to change the tap down to a normal voltage,
let alone 220 volts

How do I (cheaply) transform high voltage down 14-29 volts ac?

Id hate to loose the VFD on this mill and have to run it off a RPC
(which also puts out higher voltages)

Gunner

Variac of approiate size, or a triac type voltage regulator control.
Big ass light dimmer ?

Best Regards
Tom.

I cant get the power company to change the tap down to a normal voltage,
let alone 220 volts

Call the Corporation Comission or the Public Utility Comission or
whaever state organization regulates the power company. They have
amazing powers.

Bob AZ

On Mon, 09 May 2011 01:19:57 -0400, "Michael A. Terrell"
wrote:


Gunner Asch wrote:

Ive got a 5hp PC3 vfd running my Gorton MasterMill.
The top end voltage it is supposed to run on..is 230vts + about 5 volts
It will run down to 200 volts.
Im running it on single phase, been doing it for years.

Now the power company has increased my 220 single phase to about 249
volts and when I try to start it..I keep getting OverVoltage Alarm.

I cant get the power company to change the tap down to a normal voltage,
let alone 220 volts

How do I (cheaply) transform high voltage down 14-29 volts ac?

Id hate to loose the VFD on this mill and have to run it off a RPC
(which also puts out higher voltages)


How much current do you need? A simple buck transformer will do the
job, as long as it's secondary can handle the current.

I believe its 5.7kva

Gunner

--
"If I say two plus two is four and a Democrat says two plus two is eight,
it's not a partial victory for me when we agree that two plus two is
six. " Jonah Goldberg (modified)

On Mon, 09 May 2011 00:06:29 -0700, Gunner Asch
wrote:

On Mon, 09 May 2011 01:19:57 -0400, "Michael A. Terrell"
wrote:


Gunner Asch wrote:

Ive got a 5hp PC3 vfd running my Gorton MasterMill.
The top end voltage it is supposed to run on..is 230vts + about 5 volts
It will run down to 200 volts.
Im running it on single phase, been doing it for years.

Now the power company has increased my 220 single phase to about 249
volts and when I try to start it..I keep getting OverVoltage Alarm.

I cant get the power company to change the tap down to a normal voltage,
let alone 220 volts

How do I (cheaply) transform high voltage down 14-29 volts ac?

Id hate to loose the VFD on this mill and have to run it off a RPC
(which also puts out higher voltages)


How much current do you need? A simple buck transformer will do the
job, as long as it's secondary can handle the current.

I believe its 5.7kva

Gunner

Ok...Im going to look REALLY stupid here. Sigh..blame it on the stroke.
Or not..shrug

Ive got a BUNCH of 120/240 transformers..all marked 120/240 12/24

So if I wire one up to 240..does it mean that it will REDUCE the voltage
-24 volts?

Or is the output 24 volts?

I see I havent gotten everything back from the stroke....sigh

Gunner

--
"If I say two plus two is four and a Democrat says two plus two is eight,
it's not a partial victory for me when we agree that two plus two is
six. " Jonah Goldberg (modified)

"Gunner Asch" wrote in message
...
On Mon, 09 May 2011 00:06:29 -0700, Gunner Asch
wrote:

On Mon, 09 May 2011 01:19:57 -0400, "Michael A. Terrell"
wrote:


Gunner Asch wrote:

Ive got a 5hp PC3 vfd running my Gorton MasterMill.
The top end voltage it is supposed to run on..is 230vts + about 5 volts
It will run down to 200 volts.
Im running it on single phase, been doing it for years.

Now the power company has increased my 220 single phase to about 249
volts and when I try to start it..I keep getting OverVoltage Alarm.

I cant get the power company to change the tap down to a normal
voltage,
let alone 220 volts

How do I (cheaply) transform high voltage down 14-29 volts ac?

Id hate to loose the VFD on this mill and have to run it off a RPC
(which also puts out higher voltages)


How much current do you need? A simple buck transformer will do the
job, as long as it's secondary can handle the current.

I believe its 5.7kva

Gunner

Ok...Im going to look REALLY stupid here. Sigh..blame it on the stroke.
Or not..shrug

Ive got a BUNCH of 120/240 transformers..all marked 120/240 12/24

So if I wire one up to 240..does it mean that it will REDUCE the voltage
-24 volts?

Or is the output 24 volts?

I see I havent gotten everything back from the stroke....sigh

Gunner

--
"If I say two plus two is four and a Democrat says two plus two is eight,
it's not a partial victory for me when we agree that two plus two is
six. " Jonah Goldberg (modified)

Are the transformers center tapped or do they just have 2 terminals for
input and two for output.

If the latter they are simply 10:1 ratio transformers. If you stick 120 in
you will get 12 out the secondary. Stick 240 in and you'll get 24 out.

If they are centre tapped, without seeing them I'd guess you put 240 across
the full input winding or 120 across half the input winding.

Having said all that, I'd do it myself but I'm not sure I'd advise anyone
else to try it.....

Gunner Asch wrote:

On Mon, 09 May 2011 00:06:29 -0700, Gunner Asch
wrote:

On Mon, 09 May 2011 01:19:57 -0400, "Michael A. Terrell"
wrote:


Gunner Asch wrote:

Ive got a 5hp PC3 vfd running my Gorton MasterMill.
The top end voltage it is supposed to run on..is 230vts + about 5 volts
It will run down to 200 volts.
Im running it on single phase, been doing it for years.

Now the power company has increased my 220 single phase to about 249
volts and when I try to start it..I keep getting OverVoltage Alarm.

I cant get the power company to change the tap down to a normal voltage,
let alone 220 volts

How do I (cheaply) transform high voltage down 14-29 volts ac?

Id hate to loose the VFD on this mill and have to run it off a RPC
(which also puts out higher voltages)


How much current do you need? A simple buck transformer will do the
job, as long as it's secondary can handle the current.

I believe its 5.7kva

Gunner

Ok...Im going to look REALLY stupid here. Sigh..blame it on the stroke.
Or not..shrug

Ive got a BUNCH of 120/240 transformers..all marked 120/240 12/24

So if I wire one up to 240..does it mean that it will REDUCE the voltage
-24 volts?

Or is the output 24 volts?

I see I havent gotten everything back from the stroke....sigh

If you do a search on "buck boost wiring" you will find references for
how to wire one of your transformers to "buck" your 249V down to 225V.
Basically, the 24V secondary goes in series with the feed to your RPC,
and the primary just connects to the line. The secondary amp rating at
24V has to be enough to handle the load of your RPC/machine.

http://www.jhlarson.com/ind_tables/G...uckboost01.htm

If your transformers are large enough to handle the single phase load
see single phase diagram A and you'll need only one transformer.

http://www.jhlarson.com/ind_tables/G...uckboost03.htm

If the transformers are only large enough for the three phase load
you'll need to use three of them after the RPC. See diagram F, which is
really the same as the single phase setup in triplicate.

Do plenty of voltage checks before trying to run anything to ensure you
have it wired correctly to "buck" to 225V rather than "boost" to 273V.

"Gunner Asch" wrote in message
...
Ive got a 5hp PC3 vfd running my Gorton MasterMill.
The top end voltage it is supposed to run on..is 230vts + about 5 volts
It will run down to 200 volts.
Im running it on single phase, been doing it for years.

Now the power company has increased my 220 single phase to about 249
volts and when I try to start it..I keep getting OverVoltage Alarm.


Gunner

Rough numbers--- 5hp at 240 volts is 16 amps.
That means your transformer secondary needs to handle
more than 16 amps and 25 or 30 amps would be a nice SAFETY CUSHION.
So, that's a big transformer, if you have that, then connect the secondary
in series
with one of the 240V wires, But the phase must be reversed to buck the
incoming
240V. You will have to wire up the transformer and measure, if the voltage
it high
just reverse the primary wires.
Someone posted a site hopefully with schematics, if not post back and I'll
draw
one for you.
Mikek

"Pete C." fired this volley in news:4dc7d33d$0
:

If your transformers are large enough to handle the single phase load
see single phase diagram A and you'll need only one transformer.

As an example, I run three 450 Watt Metal Halide high-bay lamps in my
barn. They were surplus, thus inexpensive, but designed to run from
208V.

I purchased a "0.25KVA" (250-"watt") buck-boost transformer that has a
240V primary, and a 32V secondary. The secondary is rated at just a
little under 8 amps at full load.

The three 450 Watt fixtures draw 6.5A total at 208V. So the 250 VA
rating of the transformer is sufficient. ('been running them every night
for 12 years off that same little grey box)

LLoyd

"amdx" fired this volley in news:c046c$4dc7d7e5
:

That means your transformer secondary needs to handle
more than 16 amps and 25 or 30 amps would be a nice SAFETY CUSHION.

That's actually not necessary, and not great practice. Transformers are
designed to run essentially forever at their rating, and "regulate" best
at near their rated load.

If you nearly doubled the ampacity of the secondary from what you needed,
the voltage drop in 'buck' could be much greater than you anticipated.

In his _particular_ case, that's not a terrible problem, since his VFD
will run down to 200V. But in some cases it could cause trouble.

LLoyd

Gunner Asch wrote:

Ive got a 5hp PC3 vfd running my Gorton MasterMill.
The top end voltage it is supposed to run on..is 230vts + about 5 volts
It will run down to 200 volts.
Im running it on single phase, been doing it for years.

Now the power company has increased my 220 single phase to about 249
volts and when I try to start it..I keep getting OverVoltage Alarm.

Well, the real problem here is the VFD has a VERY restricted operating
range. It must have been designed for 208 V only +/- a percentage.

249 V is not unusual in many places.

I cant get the power company to change the tap down to a normal voltage,
let alone 220 volts

How do I (cheaply) transform high voltage down 14-29 volts ac?
What you need is a transformer with 240 V primary and 12 - 15 V secondary
with 10 A output rating. You wire the primary across the mains, and put
the secondary in series with one of the mains wires going to the VFD.
Check the output first with the VFD disconnected. One polarity will
increase the voltage, the other will drop it by the secondary voltage
rating.

Now, if you can't find such a transformer with a 240 V primary, you could
rig up a 120 V primary transformer between one hot and the neutral to do
the same thing. The only problem is you may not have run a neutral to a
purely 240 V load. The 120 V to 12.6 V filament transformer should be
fairly easy to come by.

There are also "voltage adjusting" transformers that have multiple taps in
small steps and 240/208 autotransformers, often found in buildings with
120/208 power and 230 V window airconditioners.

Jon

Gunner Asch wrote:


Ive got a BUNCH of 120/240 transformers..all marked 120/240 12/24

So if I wire one up to 240..does it mean that it will REDUCE the voltage
-24 volts?

Or is the output 24 volts?
Most likely, the output is fully isolated, and you'd get 24 V out.
If you wire the secondary in SERIES with the mains, you can either add or
reduce the mains voltage by 24 V, depending on the polarity. Check with a
meter before you connect the output to the VFD to make sure you got the
polarity the way you need it.

Jon

On Mon, 09 May 2011 11:50:27 -0500, Jon Elson
wrote:


Now the power company has increased my 220 single phase to about 249
volts and when I try to start it..I keep getting OverVoltage Alarm.

Well, the real problem here is the VFD has a VERY restricted operating
range. It must have been designed for 208 V only +/- a percentage.

IRRC..its rated for 200-230 volts. One of the most common industrial
VFDs out there.


249 V is not unusual in many places.

I cant get the power company to change the tap down to a normal voltage,
let alone 220 volts

How do I (cheaply) transform high voltage down 14-29 volts ac?
What you need is a transformer with 240 V primary and 12 - 15 V secondary
with 10 A output rating. You wire the primary across the mains, and put
the secondary in series with one of the mains wires going to the VFD.
Check the output first with the VFD disconnected. One polarity will
increase the voltage, the other will drop it by the secondary voltage
rating.

Now, if you can't find such a transformer with a 240 V primary, you could
rig up a 120 V primary transformer between one hot and the neutral to do
the same thing. The only problem is you may not have run a neutral to a
purely 240 V load. The 120 V to 12.6 V filament transformer should be
fairly easy to come by.

There are also "voltage adjusting" transformers that have multiple taps in
small steps and 240/208 autotransformers, often found in buildings with
120/208 power and 230 V window airconditioners.

Jon

Thanks guys..Ill check it out today!

Gunner

--
"If I say two plus two is four and a Democrat says two plus two is eight,
it's not a partial victory for me when we agree that two plus two is
six. " Jonah Goldberg (modified)

"Lloyd E. Sponenburgh" wrote in message
.70...

"amdx" fired this volley in news:c046c$4dc7d7e5
:

That means your transformer secondary needs to handle
more than 16 amps and 25 or 30 amps would be a nice SAFETY CUSHION.

That's actually not necessary, and not great practice. Transformers are
designed to run essentially forever at their rating, and "regulate" best
at near their rated load.

If you nearly doubled the ampacity of the secondary from what you needed,
the voltage drop in 'buck' could be much greater than you anticipated.

In his _particular_ case, that's not a terrible problem, since his VFD
will run down to 200V. But in some cases it could cause trouble.

LLoyd

I'll argue your response a bit.

He responded with a rating of 5.7KVA this works out to 25.9 amps at 220
Volts.

Being that he'll be driving a VFD I suspect the current will have current
pulses
that may average 16 amps but may actually peak at 25 amps or more.
As far as "regulate" best at near rated load, I don't see that as true,
you will always
have I^2R losses in the wire being equal for any equal current change
whether a full
load or half load. If you are at full load near core saturation your losses
will increase
if the current increases. So regulation could actually be worse.
I agree with you on "the voltage drop in 'buck' could be much greater
than you anticipated"
if the current is not at rated load. This could work for or against him.
This may all be null as his transformer probably isn't this big.
Just my two cents, Mikek

"Jon Elson" wrote in message
news
Gunner Asch wrote:

Ive got a 5hp PC3 vfd running my Gorton MasterMill.
The top end voltage it is supposed to run on..is 230vts + about 5 volts
It will run down to 200 volts.
Im running it on single phase, been doing it for years.

Now the power company has increased my 220 single phase to about 249
volts and when I try to start it..I keep getting OverVoltage Alarm.

Well, the real problem here is the VFD has a VERY restricted operating
range. It must have been designed for 208 V only +/- a percentage.

249 V is not unusual in many places.

I cant get the power company to change the tap down to a normal voltage,
let alone 220 volts

How do I (cheaply) transform high voltage down 14-29 volts ac?
What you need is a transformer with 240 V primary and 12 - 15 V secondary
with 10 A output rating. You wire the primary across the mains, and put
the secondary in series with one of the mains wires going to the VFD.
Check the output first with the VFD disconnected. One polarity will
increase the voltage, the other will drop it by the secondary voltage
rating.

Now, if you can't find such a transformer with a 240 V primary, you could
rig up a 120 V primary transformer between one hot and the neutral to do
the same thing. The only problem is you may not have run a neutral to a
purely 240 V load. The 120 V to 12.6 V filament transformer should be
fairly easy to come by.


It's important to understand that only a relatively small portion of the
actual connected load current passes through the buck/boost "primary"
winding.

http://www.solahd.com/products/trans...ost/index.html

"The major advantages of buck-boost transformers are their low cost, compact
size and light weight. They are also more efficient and cost less than
equivalent isolation transformers. When connected as an autotransformer,
they can handle loads up to 20 times the nameplate rating. A buck-boost
transformer is the ideal solution for changing line voltage by small
amounts."


--

On 05/09/2011 12:55 AM, Gunner Asch wrote:
On Mon, 09 May 2011 00:06:29 -0700, Gunner
wrote:

On Mon, 09 May 2011 01:19:57 -0400, "Michael A. Terrell"
wrote:


Gunner Asch wrote:

Ive got a 5hp PC3 vfd running my Gorton MasterMill.
The top end voltage it is supposed to run on..is 230vts + about 5 volts
It will run down to 200 volts.
Im running it on single phase, been doing it for years.

Now the power company has increased my 220 single phase to about 249
volts and when I try to start it..I keep getting OverVoltage Alarm.

I cant get the power company to change the tap down to a normal voltage,
let alone 220 volts

How do I (cheaply) transform high voltage down 14-29 volts ac?

Id hate to loose the VFD on this mill and have to run it off a RPC
(which also puts out higher voltages)


How much current do you need? A simple buck transformer will do the
job, as long as it's secondary can handle the current.

I believe its 5.7kva

Gunner

Ok...Im going to look REALLY stupid here. Sigh..blame it on the stroke.
Or not..shrug

Ive got a BUNCH of 120/240 transformers..all marked 120/240 12/24

So if I wire one up to 240..does it mean that it will REDUCE the voltage
-24 volts?

Or is the output 24 volts?

Put 240 in, and the output will be 24VAC, in phase with the input. Wire
it up right (in 'buck'), and it'll reduce the output by 24V. Wire it up
wrong ('boost'), and it'll increase the output by 24V.

So wire it up, primary in parallel with your 240V line, and secondary in
series. Then check the voltage with a VOM. If it's 270 some-odd volts,
then just reverse the wires on _either_ the primary or secondary (not
both!) and check again -- your voltage should drop down to 225 or so.
If it's right the first time -- don't change anything!!

5.7KVA / 220V = 25A, so you need a fairly big transformer. _If_ the
transformers are all identical, and _if_ you want to go to the trouble
to get them hooked up right, you can parallel those 240V to 24V
transformers -- but you need to get it right, or you'll have a short
circuit across 48V, instead of two 24V windings helping each other. In
general if you put all the like-colored primary leads to the same
terminals and all the like-colored secondary leads terminals then you
should be safe -- I wouldn't trust that comment for a second. Instead,
you should connect up the primaries, then one by one connect up the
secondaries. Connect a pair of secondaries together _on one side_, then
check the AC voltage between the remaining wires with the transformer
powered up. If it's less than a volt, connect 'em together. If it's
48V, then swap the direction of one of the secondaries and recheck. If
you have a clamp-on current meter it's probably a good idea to make sure
there's little or no standing current in any of the secondary wires.
Keep adding transformers until the sum of the current ratings is 30A or
so, put the wad of stuff in a fireproof cabinet, don't show it to your
local fire warden, and if your place burns down don't come crying to me.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" was written for you.
See details at http://www.wescottdesign.com/actfes/actfes.html

On 05/09/2011 12:13 PM, Tim Wescott wrote:
On 05/09/2011 12:55 AM, Gunner Asch wrote:
On Mon, 09 May 2011 00:06:29 -0700, Gunner
wrote:

On Mon, 09 May 2011 01:19:57 -0400, "Michael A. Terrell"
wrote:


Gunner Asch wrote:

Ive got a 5hp PC3 vfd running my Gorton MasterMill.
The top end voltage it is supposed to run on..is 230vts + about 5
volts
It will run down to 200 volts.
Im running it on single phase, been doing it for years.

Now the power company has increased my 220 single phase to about 249
volts and when I try to start it..I keep getting OverVoltage Alarm.

I cant get the power company to change the tap down to a normal
voltage,
let alone 220 volts

How do I (cheaply) transform high voltage down 14-29 volts ac?

Id hate to loose the VFD on this mill and have to run it off a RPC
(which also puts out higher voltages)


How much current do you need? A simple buck transformer will do the
job, as long as it's secondary can handle the current.

I believe its 5.7kva

Gunner

Ok...Im going to look REALLY stupid here. Sigh..blame it on the stroke.
Or not..shrug

Ive got a BUNCH of 120/240 transformers..all marked 120/240 12/24

So if I wire one up to 240..does it mean that it will REDUCE the voltage
-24 volts?

Or is the output 24 volts?

Put 240 in, and the output will be 24VAC, in phase with the input. Wire
it up right (in 'buck'), and it'll reduce the output by 24V. Wire it up
wrong ('boost'), and it'll increase the output by 24V.

So wire it up, primary in parallel with your 240V line, and secondary in
series. Then check the voltage with a VOM. If it's 270 some-odd volts,
then just reverse the wires on _either_ the primary or secondary (not
both!) and check again -- your voltage should drop down to 225 or so. If
it's right the first time -- don't change anything!!

5.7KVA / 220V = 25A, so you need a fairly big transformer. _If_ the
transformers are all identical, and _if_ you want to go to the trouble
to get them hooked up right, you can parallel those 240V to 24V
transformers -- but you need to get it right, or you'll have a short
circuit across 48V, instead of two 24V windings helping each other. In
general if you put all the like-colored primary leads to the same
terminals and all the like-colored secondary leads terminals then you
should be safe -- I wouldn't trust that comment for a second. Instead,
you should connect up the primaries, then one by one connect up the
secondaries. Connect a pair of secondaries together _on one side_, then
check the AC voltage between the remaining wires with the transformer
powered up. If it's less than a volt, connect 'em together. If it's 48V,
then swap the direction of one of the secondaries and recheck. If you
have a clamp-on current meter it's probably a good idea to make sure
there's little or no standing current in any of the secondary wires.
Keep adding transformers until the sum of the current ratings is 30A or
so, put the wad of stuff in a fireproof cabinet, don't show it to your
local fire warden, and if your place burns down don't come crying to me.

Sorry -- 5700VA / 220V is around 25.9A. I'd aim for a buck transformer
with a 30A rating, unless you know that the VFD is lightly used. I'd
probably _still_ aim for the 30A rating.

And don't burn your place down.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" was written for you.
See details at http://www.wescottdesign.com/actfes/actfes.html

On 05/09/2011 12:11 PM, Gunner Asch wrote:
On Mon, 09 May 2011 11:50:27 -0500, Jon
wrote:


Now the power company has increased my 220 single phase to about 249
volts and when I try to start it..I keep getting OverVoltage Alarm.

Well, the real problem here is the VFD has a VERY restricted operating
range. It must have been designed for 208 V only +/- a percentage.

IRRC..its rated for 200-230 volts. One of the most common industrial
VFDs out there.

230 + 10% is 253, so maybe your unit is just a hair touchy on the limit.
Actually, when decelerating, the bus voltage rises a LOT, and you need
braking resistors to absorb the energy pulled back out of the motor.
The VFDs I've worked on don't usually turn on the braking resistor until
about 380 V (DC) and won't alarm until over 400 V (DC).

I'm wondering if a part is beginning to fail on your VFD making it more
sensitive to DC bus voltage.

Jon

On 5/8/2011 10:15 PM, Gunner Asch wrote:
Ive got a 5hp PC3 vfd running my Gorton MasterMill.
The top end voltage it is supposed to run on..is 230vts + about 5 volts
It will run down to 200 volts.
Im running it on single phase, been doing it for years.

Now the power company has increased my 220 single phase to about 249
volts and when I try to start it..I keep getting OverVoltage Alarm.

I cant get the power company to change the tap down to a normal voltage,
let alone 220 volts

How do I (cheaply) transform high voltage down 14-29 volts ac?

Id hate to loose the VFD on this mill and have to run it off a RPC
(which also puts out higher voltages)

Gunner



Hmmmmm.... Is there a state regulatory agency you can complain to? In
Az we would document a request to restore electrical voltage levels to
those previously experienced as the new changes are causing personal
equipment to operate improperly. Mailed, return receipt, etc. Then we
would file a complaint with the Arizona Corporation Commission.
Documenting the phone calls, who you spoke with, written request, and
written response if any.

Its my understanding however that the power companies want to keep
upping the voltage because higher voltages distribute better. Its going
to be a never ending uphill battle.

On Mon, 09 May 2011 14:17:55 -0500, Jon Elson wrote:

On 05/09/2011 12:11 PM, Gunner Asch wrote:
On Mon, 09 May 2011 11:50:27 -0500, Jon
wrote:


Now the power company has increased my 220 single phase to about 249
volts and when I try to start it..I keep getting OverVoltage Alarm.

Well, the real problem here is the VFD has a VERY restricted operating
range. It must have been designed for 208 V only +/- a percentage.

IRRC..its rated for 200-230 volts. One of the most common industrial
VFDs out there.

230 + 10% is 253, so maybe your unit is just a hair touchy on the limit.
Actually, when decelerating, the bus voltage rises a LOT, and you need
braking resistors to absorb the energy pulled back out of the motor.
The VFDs I've worked on don't usually turn on the braking resistor until
about 380 V (DC) and won't alarm until over 400 V (DC).

I'm wondering if a part is beginning to fail on your VFD making it more
sensitive to DC bus voltage.

Jon

Thats entirely possible. On the other hand..they make 220-240 VFDs as
well. And of course..Im running 3 ph out of a single phase input..with
no wire on L3.

Ive got some BIG buck-boost transformers out there..Ive even got a
backplane with 3 on it, evidently used for 3 phase in/out.

Im chopping my way through the weeds this afternoon and Ill start taking
them off the racks in a little bit.

Gunner

--
"If I say two plus two is four and a Democrat says two plus two is eight,
it's not a partial victory for me when we agree that two plus two is
six. " Jonah Goldberg (modified)

On Mon, 09 May 2011 12:15:05 -0700, Tim Wescott
wrote:

On 05/09/2011 12:13 PM, Tim Wescott wrote:
On 05/09/2011 12:55 AM, Gunner Asch wrote:
On Mon, 09 May 2011 00:06:29 -0700, Gunner
wrote:

On Mon, 09 May 2011 01:19:57 -0400, "Michael A. Terrell"
wrote:


Gunner Asch wrote:

Ive got a 5hp PC3 vfd running my Gorton MasterMill.
The top end voltage it is supposed to run on..is 230vts + about 5
volts
It will run down to 200 volts.
Im running it on single phase, been doing it for years.

Now the power company has increased my 220 single phase to about 249
volts and when I try to start it..I keep getting OverVoltage Alarm.

I cant get the power company to change the tap down to a normal
voltage,
let alone 220 volts

How do I (cheaply) transform high voltage down 14-29 volts ac?

Id hate to loose the VFD on this mill and have to run it off a RPC
(which also puts out higher voltages)


How much current do you need? A simple buck transformer will do the
job, as long as it's secondary can handle the current.

I believe its 5.7kva

Gunner

Ok...Im going to look REALLY stupid here. Sigh..blame it on the stroke.
Or not..shrug

Ive got a BUNCH of 120/240 transformers..all marked 120/240 12/24

So if I wire one up to 240..does it mean that it will REDUCE the voltage
-24 volts?

Or is the output 24 volts?

Put 240 in, and the output will be 24VAC, in phase with the input. Wire
it up right (in 'buck'), and it'll reduce the output by 24V. Wire it up
wrong ('boost'), and it'll increase the output by 24V.

So wire it up, primary in parallel with your 240V line, and secondary in
series. Then check the voltage with a VOM. If it's 270 some-odd volts,
then just reverse the wires on _either_ the primary or secondary (not
both!) and check again -- your voltage should drop down to 225 or so. If
it's right the first time -- don't change anything!!

5.7KVA / 220V = 25A, so you need a fairly big transformer. _If_ the
transformers are all identical, and _if_ you want to go to the trouble
to get them hooked up right, you can parallel those 240V to 24V
transformers -- but you need to get it right, or you'll have a short
circuit across 48V, instead of two 24V windings helping each other. In
general if you put all the like-colored primary leads to the same
terminals and all the like-colored secondary leads terminals then you
should be safe -- I wouldn't trust that comment for a second. Instead,
you should connect up the primaries, then one by one connect up the
secondaries. Connect a pair of secondaries together _on one side_, then
check the AC voltage between the remaining wires with the transformer
powered up. If it's less than a volt, connect 'em together. If it's 48V,
then swap the direction of one of the secondaries and recheck. If you
have a clamp-on current meter it's probably a good idea to make sure
there's little or no standing current in any of the secondary wires.
Keep adding transformers until the sum of the current ratings is 30A or
so, put the wad of stuff in a fireproof cabinet, don't show it to your
local fire warden, and if your place burns down don't come crying to me.

Sorry -- 5700VA / 220V is around 25.9A. I'd aim for a buck transformer
with a 30A rating, unless you know that the VFD is lightly used. I'd
probably _still_ aim for the 30A rating.

And don't burn your place down.

Indeed. I am running a 3hp motor on the Gorton MasterMill..so Im not
running it very hard. More short runs than anything else....Short being
relative of course.

Gunner

--
"If I say two plus two is four and a Democrat says two plus two is eight,
it's not a partial victory for me when we agree that two plus two is
six. " Jonah Goldberg (modified)

Gunner Asch wrote:
Ive got a 5hp PC3 vfd running my Gorton MasterMill.
The top end voltage it is supposed to run on..is 230vts + about 5 volts
It will run down to 200 volts.
Im running it on single phase, been doing it for years.

Now the power company has increased my 220 single phase to about 249
volts and when I try to start it..I keep getting OverVoltage Alarm.

I cant get the power company to change the tap down to a normal voltage,
let alone 220 volts

How do I (cheaply) transform high voltage down 14-29 volts ac?

Id hate to loose the VFD on this mill and have to run it off a RPC
(which also puts out higher voltages)

If it's an "ou" error, have you tried setting a higer detection level
constant? Page 8-18 in the manual.

http://www.yaskawa.com/.../TOE-606-3...A%20&%20E).pdf

Gunner Asch wrote:

How do I (cheaply) transform high voltage down 14-29 volts ac?

Id hate to loose the VFD on this mill and have to run it off a RPC
(which also puts out higher voltages)

I wonder what the voltage drop would be across a couple electric range elements?

Wes

On May 9, 6:40*am, "Pete C." wrote:
Gunner Asch wrote:

On Mon, 09 May 2011 00:06:29 -0700, Gunner Asch
wrote:

On Mon, 09 May 2011 01:19:57 -0400, "Michael A. Terrell"
wrote:

Gunner Asch wrote:

Ive got a 5hp PC3 vfd running my Gorton MasterMill.
The top end voltage it is supposed to run on..is 230vts + about 5 volts
It will run down to 200 volts.
Im running it on single phase, been doing it for years.

Now the power company has increased my 220 single phase to about 249
volts and when I try to start it..I keep getting OverVoltage Alarm.

I cant get the power company to change the tap down to a normal voltage,
let alone 220 volts

How do I (cheaply) transform high voltage down 14-29 volts ac?

Id hate to loose the VFD on this mill and have to run it off a RPC
(which also puts out higher voltages)

* How much current do you need? *A simple buck transformer will do the
job, as long as it's secondary can handle the current.

I believe its 5.7kva

Gunner

Ok...Im going to look REALLY stupid here. Sigh..blame it on the stroke.
Or not..shrug

Ive got a BUNCH of 120/240 transformers..all marked 120/240 * 12/24

So if I wire one up to 240..does it mean that it will REDUCE the voltage
-24 volts?

Or is the output 24 volts?

I see I havent gotten everything back from the stroke....sigh

If you do a search on "buck boost wiring" you will find references for
how to wire one of your transformers to "buck" your 249V down to 225V.
Basically, the 24V secondary goes in series with the feed to your RPC,
and the primary just connects to the line. The secondary amp rating at
24V has to be enough to handle the load of your RPC/machine.

http://www.jhlarson.com/ind_tables/G...uckboost01.htm

If your transformers are large enough to handle the single phase load
see single phase diagram A and you'll need only one transformer.

http://www.jhlarson.com/ind_tables/G...uckboost03.htm

If the transformers are only large enough for the three phase load
you'll need to use three of them after the RPC. See diagram F, which is
really the same as the single phase setup in triplicate.

NOOOO !!

Never put a transformer in the Output of a VFD!
It is variable frequency... Those transformers are NOT going to be
amused with 20 HZ !!

Keep the Buck transformers in the Line side, where they get 60 hz.
just the way they like it..

Gunner Asch wrote:
Ive got a 5hp PC3 vfd running my Gorton MasterMill.
The top end voltage it is supposed to run on..is 230vts + about 5 volts
It will run down to 200 volts.
Im running it on single phase, been doing it for years.

Now the power company has increased my 220 single phase to about 249
volts and when I try to start it..I keep getting OverVoltage Alarm.

I cant get the power company to change the tap down to a normal voltage,
let alone 220 volts

How do I (cheaply) transform high voltage down 14-29 volts ac?

Id hate to loose the VFD on this mill and have to run it off a RPC
(which also puts out higher voltages)

If it's an "ou" error, have you tried setting a higer detection level
constant? Page 8-18 in the manual.

http://www.yaskawa.com/.../TOE-606-3...A%20&%20E).pdf

On Mon, 09 May 2011 13:26:14 -0700, Bob La Londe
wrote:

On 5/8/2011 10:15 PM, Gunner Asch wrote:


I cant get the power company to change the tap down to a normal voltage,
let alone 220 volts


Hmmmmm.... Is there a state regulatory agency you can complain to? In
Az we would document a request to restore electrical voltage levels to
those previously experienced as the new changes are causing personal
equipment to operate improperly. Mailed, return receipt, etc. Then we
would file a complaint with the Arizona Corporation Commission.
Documenting the phone calls, who you spoke with, written request, and
written response if any.

Its my understanding however that the power companies want to keep
upping the voltage because higher voltages distribute better. Its going
to be a never ending uphill battle.

240 +/- 5% (228 to 252 volts) has been the standard supply voltage in
the US for quite some time.

--
Ned Simmons

On Mon, 9 May 2011 14:43:24 -0700 (PDT), Cross-Slide
wrote:


Or is the output 24 volts?

I see I havent gotten everything back from the stroke....sigh

If you do a search on "buck boost wiring" you will find references for
how to wire one of your transformers to "buck" your 249V down to 225V.
Basically, the 24V secondary goes in series with the feed to your RPC,
and the primary just connects to the line. The secondary amp rating at
24V has to be enough to handle the load of your RPC/machine.

http://www.jhlarson.com/ind_tables/G...uckboost01.htm

If your transformers are large enough to handle the single phase load
see single phase diagram A and you'll need only one transformer.

http://www.jhlarson.com/ind_tables/G...uckboost03.htm

If the transformers are only large enough for the three phase load
you'll need to use three of them after the RPC. See diagram F, which is
really the same as the single phase setup in triplicate.

NOOOO !!

Never put a transformer in the Output of a VFD!
It is variable frequency... Those transformers are NOT going to be
amused with 20 HZ !!

Keep the Buck transformers in the Line side, where they get 60 hz.
just the way they like it..

Correct. Even I remembered this G

Gunner

--
"If I say two plus two is four and a Democrat says two plus two is eight,
it's not a partial victory for me when we agree that two plus two is
six. " Jonah Goldberg (modified)

PrecisionmachinisT wrote:

... [quoting SolaHD]
... When connected as an autotransformer, ...

What? How's that work?

Bob

Bob Engelhardt fired this volley in
:

What? How's that work?

If you think about it, it cannot act otherwise. One leg of the secondary
and one leg of the primary are tied to the same line leg. The other line
leg is tied to the _other_ end of the primary.

That is an autoformer. It is not necessary for the line input to span both
the primary and secondary for it to qualify, only that the primary and
secondary be common at one of their legs.

LLoyd

"Lloyd E. Sponenburgh" lloydspinsidemindspring.com fired this volley
in . 3.70:

That is an autoformer. It is not necessary for the line input to span
both the primary and secondary for it to qualify, only that the
primary and secondary be common at one of their legs.

But I might add, that a buck-boost arrangement could be made to work in
buck by running the line across both primary and secondary, then taking the
one load line off the junction between the two. (and vice versa)

LLoyd

"Lloyd E. Sponenburgh" lloydspinsidemindspring.com fired this volley
in . 3.70:

That is an autoformer. It is not necessary for the line input to span
both the primary and secondary for it to qualify, only that the
primary and secondary be common at one of their legs.

Oh.. and it gets "messy" in boost G.

LLoyd

"Bob Engelhardt" wrote in message
...
PrecisionmachinisT wrote:

... [quoting SolaHD]
... When connected as an autotransformer, ...

What? How's that work?



Most of the energy ( wattage or kva ) passes directly from line to load
THROUGH the secondary winding instead of INTO it.

Don't quote me but recalling it goes something like this:

A transformer with 24 volt X 10amps output capacity at secondary = 240 watts
but since ampacity is dependant on conductor cros sectional diameter then at
240 volts this comes out to be 2400 watts instead

--In reality, some amperage actually does pass from primary to secondary via
induction but it is nowhere near 2400 watts...and so while the above only
tells part of the story, rather than try and explain I suggest look it up if
you're truly interested.


--

Gunner Asch wrote:
Ive got a 5hp PC3 vfd running my Gorton MasterMill.
The top end voltage it is supposed to run on..is 230vts + about 5 volts
It will run down to 200 volts.
Im running it on single phase, been doing it for years.

Now the power company has increased my 220 single phase to about 249
volts and when I try to start it..I keep getting OverVoltage Alarm.

I cant get the power company to change the tap down to a normal voltage,
let alone 220 volts

How do I (cheaply) transform high voltage down 14-29 volts ac?

Id hate to loose the VFD on this mill and have to run it off a RPC
(which also puts out higher voltages)

Gunner



A simple buck/boost transformer installed.

John

Gunner Asch wrote:

Ive got a 5hp PC3 vfd running my Gorton MasterMill.
The top end voltage it is supposed to run on..is 230vts + about 5 volts
It will run down to 200 volts.
Im running it on single phase, been doing it for years.

Now the power company has increased my 220 single phase to about 249
volts and when I try to start it..I keep getting OverVoltage Alarm.

I cant get the power company to change the tap down to a normal voltage,
let alone 220 volts

How do I (cheaply) transform high voltage down 14-29 volts ac?

Id hate to loose the VFD on this mill and have to run it off a RPC
(which also puts out higher voltages)


A buck transformer.

Get a 240v/24v transformer, that has a 24v secondary current rating that's
at least as much as whatever you need from the 250v line. Connect the
primary of the buck transformer to the line, and put the 24v secondary in
series with the 250v supply, in reverse polarity. That will subtract the
24v from the 250v. line, leaving 226. Of if you need different exact
numbers, I'm sure that you're capable of doing the math. :-)

Hope This Helps!
Rich

Gunner Asch wrote:

On Mon, 9 May 2011 14:43:24 -0700 (PDT), Cross-Slide
wrote:


Or is the output 24 volts?

I see I havent gotten everything back from the stroke....sigh

If you do a search on "buck boost wiring" you will find references for
how to wire one of your transformers to "buck" your 249V down to 225V.
Basically, the 24V secondary goes in series with the feed to your RPC,
and the primary just connects to the line. The secondary amp rating at
24V has to be enough to handle the load of your RPC/machine.

http://www.jhlarson.com/ind_tables/G...uckboost01.htm

If your transformers are large enough to handle the single phase load
see single phase diagram A and you'll need only one transformer.

http://www.jhlarson.com/ind_tables/G...uckboost03.htm

If the transformers are only large enough for the three phase load
you'll need to use three of them after the RPC. See diagram F, which is
really the same as the single phase setup in triplicate.

NOOOO !!

Never put a transformer in the Output of a VFD!
It is variable frequency... Those transformers are NOT going to be
amused with 20 HZ !!

Keep the Buck transformers in the Line side, where they get 60 hz.
just the way they like it..

Correct. Even I remembered this G

Except we're talking about an RPC, not a VFD.

Gunner Asch wrote:

Ive got a 5hp PC3 vfd running my Gorton MasterMill.
The top end voltage it is supposed to run on..is 230vts + about 5 volts
It will run down to 200 volts.
Im running it on single phase, been doing it for years.

Now the power company has increased my 220 single phase to about 249
volts and when I try to start it..I keep getting OverVoltage Alarm.

I cant get the power company to change the tap down to a normal voltage,
let alone 220 volts

How do I (cheaply) transform high voltage down 14-29 volts ac?

Id hate to loose the VFD on this mill and have to run it off a RPC
(which also puts out higher voltages)

Well, someone else already suggested the buck transformer, but here's
a thought - does the VFD have input taps that can select the higher
voltage input?

Good Luck!
Rich

Dennis wrote:
"Gunner Asch" wrote in message

Ok...Im going to look REALLY stupid here. Sigh..blame it on the stroke.
Or not..shrug

The only stupid question is the one you don't ask. :-)

Ive got a BUNCH of 120/240 transformers..all marked 120/240 12/24

So if I wire one up to 240..does it mean that it will REDUCE the voltage
-24 volts?

Or is the output 24 volts?

I see I havent gotten everything back from the stroke....sigh

Are the transformers center tapped or do they just have 2 terminals for
input and two for output.

If the latter they are simply 10:1 ratio transformers. If you stick 120 in
you will get 12 out the secondary. Stick 240 in and you'll get 24 out.

If they are centre tapped, without seeing them I'd guess you put 240
across the full input winding or 120 across half the input winding.

Having said all that, I'd do it myself but I'm not sure I'd advise anyone
else to try it.....

I've seen transformers with two 120V primaries that you wire in series
for 240V input, or parallel for 120V. This one might also have two
secondaries, that would be used the same way; I'd have to see the tranny.

(it seems I'm about the third one so far to suggest the buck transformer.)

Cheers!
Rich

Wes wrote:
Gunner Asch wrote:

How do I (cheaply) transform high voltage down 14-29 volts ac?

Id hate to loose the VFD on this mill and have to run it off a RPC
(which also puts out higher voltages)

I wonder what the voltage drop would be across a couple electric range
elements?

It's irrelevant, because that is a Very Bad Idea.

Hope This Helps!
Rich

On 2011-05-09, Gunner Asch wrote:
On Mon, 09 May 2011 00:06:29 -0700, Gunner Asch
wrote:

On Mon, 09 May 2011 01:19:57 -0400, "Michael A. Terrell"
wrote:


Gunner Asch wrote:

[ ... ]

How do I (cheaply) transform high voltage down 14-29 volts ac?

[ ... ]

How much current do you need? A simple buck transformer will do the
job, as long as it's secondary can handle the current.

I believe its 5.7kva

Gunner

Ok...Im going to look REALLY stupid here. Sigh..blame it on the stroke.
Or not..shrug

Ive got a BUNCH of 120/240 transformers..all marked 120/240 12/24

So if I wire one up to 240..does it mean that it will REDUCE the voltage
-24 volts?

Or is the output 24 volts?

I see I havent gotten everything back from the stroke....sigh

The input has two windings, which if connected in parallel are
120 VAC input, and if connected in series are 240 VAC.

The output side is similar, but with two windings which are each
12 VAC, and which connected in series will be 24 VAC -- about what you
need. The question is whether they will handle enough current. If about
half the current you need, use two of them, and wire the output windings
of each transformer in parallel for 12 VAC, and hook the secondary
windings of the two transformers in series -- working from my (just)
previously posted ASCII graphics.

If you have a very heavy duty Variac or Powerstat which can
handle 240 VAC -- they typically have multiple taps so you can get
overvoltage out of them. Wire the input voltage to the full ends of the
winding, and the output one tap down from the end. (You can even use
the wiper to provide variable voltage to something else (not when your
machine is running) if you need that. Again -- *you* are likely to have
a Variac or Powerstat which you can barely lift sitting around, and
that would be what you need for this.

Good Luck,
DoN.

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