I have a Sheppach table saw which constantly blows the fuse on startup. On the motor it says 14.5 amps at 230 volts, which I interpret to be about 4 1/2 horsepower. I share my power with a bathroom fixtures supplier, and they have the keys to the fuse box. Daytimes it's no problem. They are friendly enough about switching my power back on. But, if they aren't there and the power goes off, then I'm stuck for the day. People have suggested UPS's, but I don't see any fit for my application. Any way to simply limit the current spike for this motor on startup?

On 1/28/2014 20:07, robobass wrote:
I have a Sheppach table saw which constantly blows the fuse on
startup. On the motor it says 14.5 amps at 230 volts, which I
interpret to be about 4 1/2 horsepower. I share my power with a
bathroom fixtures supplier, and they have the keys to the fuse box.
Daytimes it's no problem. They are friendly enough about switching my
power back on. But, if they aren't there and the power goes off, then
I'm stuck for the day. People have suggested UPS's, but I don't see
any fit for my application. Any way to simply limit the current spike
for this motor on startup?

Softstarter?
Variac for ramping voltage up slowly manually?

robobass wrote:

I have a Sheppach table saw which constantly blows the fuse on startup.

The first thing you might try is changing the breaker. As they get
old they tend to trip at lower current and repeated trippings will
accelerate the aging process.

-jim

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On 1/28/14, 10:54 AM, jim wrote:


robobass wrote:

I have a Sheppach table saw which constantly blows the fuse on startup.

The first thing you might try is changing the breaker. As they get
old they tend to trip at lower current and repeated trippings will
accelerate the aging process.

-jim

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+1

Erik

On 28/01/14 18:07, robobass wrote:
I have a Sheppach table saw which constantly blows the fuse on startup. On the motor it says 14.5 amps at 230 volts, which I interpret to be about 4 1/2 horsepower. I share my power with a bathroom fixtures supplier, and they have the keys to the fuse box. Daytimes it's no problem. They are friendly enough about switching my power back on. But, if they aren't there and the power goes off, then I'm stuck for the day. People have suggested UPS's, but I don't see any fit for my application. Any way to simply limit the current spike for this motor on startup?
Fuse or circuit breaker?

I've seen this problem in a workshop I frequent in the UK where a
diamond saw would frequently trip the breaker on start-up even though
the motor run current was well below the breaker rating. IIRC a 1.5hp
motor and a 16A single phase supply, the saw motor having additional
inertia loads of the saw blade via a small belt reduction. The breaker
turned out to be unsuitable for motor starting loads, IIRC it was a B
class breaker and when swapped to a C class the problem went away. Still
a 16A breaker but its trip characteristics were tailored to motor start
loads or similar. I had discussed this with a couple of electricians and
both agreed that was the issue but it just seems difficult to get them
in as they all seem busy, the second one did get the chance to change
the breaker and all then sorted and certified.

robobass wrote:

I have a Sheppach table saw which constantly blows the fuse on startup. On
the motor it says 14.5 amps at 230 volts, which I interpret to be about 4
1/2 horsepower. I share my power with a bathroom fixtures supplier, and
they have the keys to the fuse box. Daytimes it's no problem. They are
friendly enough about switching my power back on. But, if they aren't
there and the power goes off, then I'm stuck for the day. People have
suggested UPS's, but I don't see any fit for my application. Any way to
simply limit the current spike for this motor on startup?
If you can get a motor-rated breaker, that would be a big help.
Otherwise, get a 3-phase motor, if possible, and a VFD. The VFD
can be programmed for and rate of starting ramp-up you desire.
This will prevent it from drawing a big surge at start-up.

Jon

On Tue, 28 Jan 2014 10:07:52 -0800 (PST), robobass
wrote:

I have a Sheppach table saw which constantly blows the fuse on startup. On the motor it says 14.5 amps at 230 volts, which I interpret to be about 4 1/2 horsepower. I share my power with a bathroom fixtures supplier, and they have the keys to the fuse box. Daytimes it's no problem. They are friendly enough about switching my power back on. But, if they aren't there and the power goes off, then I'm stuck for the day. People have suggested UPS's, but I don't see any fit for my application. Any way to simply limit the current spike for this motor on startup?

Possibles:

1- Replace regular fuse with same-amp slo-blow fuse type.
2- Replace regular fuse with same-amp circuit breaker.
3- Install a slightly larger fuse in the circuit.
4- Call Sheppach and ask them for advice.

#3 is not code-approved, but it's not really dangerous. I've seen
people replace 15A fuses with 20-ampers and never get into trouble,
but a possibility is there (for -sustained- higher-than-normal load)
And the bathroom fixtures supplier shouldn't have any problem at all
with #1 or 2.

--
I have the consolation of having added nothing to my private fortune during
my public service, and of retiring with hands clean as they are empty.
-- Thomas Jefferson, letter to Count Diodati, 1807

Too bad -none- of the current CONgresscritters are willing to do that. -LJ

On Tue, 28 Jan 2014 10:07:52 -0800 (PST), robobass
wrote:

I have a Sheppach table saw which constantly blows the fuse on startup. On the motor it says 14.5 amps at 230 volts, which I interpret to be about 4 1/2 horsepower. I share my power with a bathroom fixtures supplier, and they have the keys to the fuse box. Daytimes it's no problem. They are friendly enough about switching my power back on. But, if they aren't there and the power goes off, then I'm stuck for the day. People have suggested UPS's, but I don't see any fit for my application. Any way to simply limit the current spike for this motor on startup?
A 50 foot extention cord would likely do it - particularly if it is a
bit light - - - -

What is the circuit fused at?? Would a time delay fuse (aka fusetron)
solve the startup current problem??

On Tue, 28 Jan 2014 12:54:30 -0600, jim
wrote:



robobass wrote:

I have a Sheppach table saw which constantly blows the fuse on startup.

The first thing you might try is changing the breaker. As they get
old they tend to trip at lower current and repeated trippings will
accelerate the aging process.

-jim

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The OP DID say "blows the fuse", so if that is true, there is no
brewaker to deteriorate.

On Tue, 28 Jan 2014 13:47:51 -0600, Jon Elson
wrote:

robobass wrote:

I have a Sheppach table saw which constantly blows the fuse on startup. On
the motor it says 14.5 amps at 230 volts, which I interpret to be about 4
1/2 horsepower. I share my power with a bathroom fixtures supplier, and
they have the keys to the fuse box. Daytimes it's no problem. They are
friendly enough about switching my power back on. But, if they aren't
there and the power goes off, then I'm stuck for the day. People have
suggested UPS's, but I don't see any fit for my application. Any way to
simply limit the current spike for this motor on startup?
If you can get a motor-rated breaker, that would be a big help.
Otherwise, get a 3-phase motor, if possible, and a VFD. The VFD
can be programmed for and rate of starting ramp-up you desire.
This will prevent it from drawing a big surge at start-up.

Jon
If it is 4HP there is a very STRONG chance it can be re-jumpered for
240 volts. I had the same problem with my compressor - 240 fixed it.

"robobass" wrote in message
...
I have a Sheppach table saw which constantly blows the fuse on
startup. On the motor it says 14.5 amps at 230 volts, which I
interpret to be about 4 1/2 horsepower. I share my power with a
bathroom fixtures supplier, and they have the keys to the fuse box.
Daytimes it's no problem. They are friendly enough about switching my
power back on. But, if they aren't there and the power goes off, then
I'm stuck for the day. People have suggested UPS's, but I don't see
any fit for my application. Any way to simply limit the current spike
for this motor on startup?

=================
http://www.ametherm.com/inrush-curre...t-limiter.html
jsw

wrote:

On Tue, 28 Jan 2014 12:54:30 -0600, jim
wrote:



robobass wrote:

I have a Sheppach table saw which constantly blows the fuse on startup.

They are friendly enough about switching my power back on.

The first thing you might try is changing the breaker. As they get
old they tend to trip at lower current and repeated trippings will
accelerate the aging process.

-jim

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The OP DID say "blows the fuse", so if that is true, there is no
brewaker to deteriorate.

I'm guessing there is a breaker since he said they don't
mind switching it back on.

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On 2014-01-28, robobass wrote:

I have a Sheppach table saw which constantly blows the fuse on
startup. On the motor it says 14.5 amps at 230 volts, which I interpret
to be about 4 1/2 horsepower. I share my power with a bathroom fixtures
supplier, and they have the keys to the fuse box. Daytimes it's no
problem. They are friendly enough about switching my power back on. But,
if they aren't there and the power goes off, then I'm stuck for the day.
People have suggested UPS's, but I don't see any fit for my application.
Any way to simply limit the current spike for this motor on startup?

You've gotten suggestions to get a motor rated breaker, which
would be the proper choice.

However -- at 4-1/2 HP, you are in the size range where a
three-phase motor is a good fit. If that motor *is* three phase, then
consider getting a VFD to go between it and the wall. A VFD can be
configured to take however long you like to spin up to full speed, and
in the process to reduce the starting current significantly. (Even if
you have no benefit from the variable speed part of it all. :-)

Enjoy,
DoN.

--
Remove oil spill source from e-mail
Email: | (KV4PH) Voice (all times): (703) 938-4564
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--- Black Holes are where God is dividing by zero ---

On 2014-01-29, wrote:
On Tue, 28 Jan 2014 13:47:51 -0600, Jon Elson
wrote:

robobass wrote:

I have a Sheppach table saw which constantly blows the fuse on startup. On
the motor it says 14.5 amps at 230 volts, which I interpret to be about 4
1/2 horsepower. I share my power with a bathroom fixtures supplier, and

[ ... ]

Jon
If it is 4HP there is a very STRONG chance it can be re-jumpered for
240 volts. I had the same problem with my compressor - 240 fixed it.

He is *already* running at 230 VAC which is just another way of
saying 240 VAC these days. Normal outlet voltage has been changing over
the years. I remember some equipment rated at 110 V, then 115 V, then
117 V, and now 120 V. 230/240 is simply double whichever voltage is the
current one.

And 14.5 A is pretty high for an outlet-connected motor, and
would be certain to pop a 15A breaker. If the wiring is heavy-duty, he
may have 20A braker and outlets. But a motor rated breaker, with the
curve which allows longer/higher start-up currents while working at the
normal current for really long-term power drains..

Enjoy,
DoN.

--
Remove oil spill source from e-mail
Email: | (KV4PH) Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

DoN. Nichols pretended :
On 2014-01-29, wrote:
On Tue, 28 Jan 2014 13:47:51 -0600, Jon Elson
wrote:

robobass wrote:

I have a Sheppach table saw which constantly blows the fuse on startup. On
the motor it says 14.5 amps at 230 volts, which I interpret to be about 4
1/2 horsepower. I share my power with a bathroom fixtures supplier, and

[ ... ]

Jon
If it is 4HP there is a very STRONG chance it can be re-jumpered for
240 volts. I had the same problem with my compressor - 240 fixed it.

He is *already* running at 230 VAC which is just another way of
saying 240 VAC these days. Normal outlet voltage has been changing over
the years. I remember some equipment rated at 110 V, then 115 V, then
117 V, and now 120 V. 230/240 is simply double whichever voltage is the
current one.
Does he mean "change the motor jumpers from 230 to 240" if it has taps
to do that?

And 14.5 A is pretty high for an outlet-connected motor, and
would be certain to pop a 15A breaker. If the wiring is heavy-duty, he
may have 20A braker and outlets. But a motor rated breaker, with the
curve which allows longer/higher start-up currents while working at the
normal current for really long-term power drains..

Enjoy,
DoN.

--
John G

Thanks everyone for all the advice. To clarify, it's a 16 amp breaker, 230v.. I haven't looked at it, but it's almost certainly not a special "motor rated breaker". I'll try that first, as that would be quick and cheap. I didn't realize until last night how big that motor was. In principal I have 3.8kw on the circuit, which I have been abusing, running about 3kw for heating and not always shutting that down before starting up the saw. The box is close by, and it would be easy enough to run another circuit or two to the shop, but the toilet guys are typical cautious Germans and won't let me do it myself. Paying an electrician to do it would naturally be expensive, but I suppose I'll have to bite the bullet at some point. For now I just have to be diligent about managing my current draw.

On 29/01/14 05:48, DoN. Nichols wrote:
On 2014-01-29, wrote:
On Tue, 28 Jan 2014 13:47:51 -0600, Jon Elson
wrote:

robobass wrote:

I have a Sheppach table saw which constantly blows the fuse on startup. On
the motor it says 14.5 amps at 230 volts, which I interpret to be about 4
1/2 horsepower. I share my power with a bathroom fixtures supplier, and
[ ... ]

Jon
If it is 4HP there is a very STRONG chance it can be re-jumpered for
240 volts. I had the same problem with my compressor - 240 fixed it.
He is *already* running at 230 VAC which is just another way of
saying 240 VAC these days. Normal outlet voltage has been changing over
the years. I remember some equipment rated at 110 V, then 115 V, then
117 V, and now 120 V. 230/240 is simply double whichever voltage is the
current one.
Except that from the OPs other postings he is based in Germany and this
will be running off a single phase 230V supply not a US type centre
tapped style supply so the 110V to 120V changes have no bearing.


And 14.5 A is pretty high for an outlet-connected motor, and
would be certain to pop a 15A breaker. If the wiring is heavy-duty, he
may have 20A braker and outlets. But a motor rated breaker, with the
curve which allows longer/higher start-up currents while working at the
normal current for really long-term power drains..

Enjoy,
DoN.

On Wed, 29 Jan 2014 02:44:10 -0800 (PST), robobass
wrote:


Thanks everyone for all the advice. To clarify, it's a 16 amp breaker, 230v. I haven't looked at it, but it's almost certainly not a special "motor rated breaker". I'll try that first, as that would be quick and cheap. I didn't realize until last night how big that motor was. In principal I have 3.8kw on the circuit, which I have been abusing, running about 3kw for heating and not always shutting that down before starting up the saw. The box is close by, and it would be easy enough to run another circuit or two to the shop, but the toilet guys are typical cautious Germans and won't let me do it myself. Paying an electrician to do it would naturally be expensive, but I suppose I'll have to bite the bullet at some point. For now I just have to be diligent about managing my current draw.

Ask if you could do the work yourself and then let the electrician
connect it all up for you. That'll save you a lot of money. Find an
electrician who'll do it for you, then check with the store owners.

You shouldn't have a saw and heater on the same line, anyway. It's no
wonder you're blowing breakers.

--
I have the consolation of having added nothing to my private fortune during
my public service, and of retiring with hands clean as they are empty.
-- Thomas Jefferson, letter to Count Diodati, 1807

Too bad -none- of the current CONgresscritters are willing to do that. -LJ

Except that from the OPs other postings he is based in Germany and this

will be running off a single phase 230V supply not a US type centre

tapped style supply so the 110V to 120V changes have no bearing.


Correct.
AFAIK, we don't even do three phase here, just single phase 230 and 400. 400 is preferred for stoves and electric water and room heaters, which are common here since gas is more expensive than in US, but most older buildings don't have it. In my apartment building, we do central heat and hot water with a gas boiler in the cellar, but no gas to the units. Also interesting, most industrial machinery runs only on 400v, and the motors are rarely convertible. There is a lot of nonscientific thought here. I was warned to avoid a 230v lathe, even though it was only 750w. I was like..."your microwave oven (also distrusted here) sucks more power than that! What's wrong with running a lathe with 230v?"

Ask if you could do the work yourself and then let the electrician

connect it all up for you. That'll save you a lot of money. Find an

electrician who'll do it for you, then check with the store owners.

Yes, that's the plan. It will still be expensive though. These guys here are insane, and people put up with it.


You shouldn't have a saw and heater on the same line, anyway. It's no

wonder you're blowing breakers.

Agreed. No choice at the moment. Only one line.

On Wednesday, January 29, 2014 9:13:12 AM UTC-5, robobass wrote:


You shouldn't have a saw and heater on the same line, anyway. It's no



wonder you're blowing breakers.



Agreed. No choice at the moment. Only one line.

When the motor is running, it is putting heat into the building, so you do not need the heater when using the saw. _So you could add a relay activated by turning on the saw. The relay would cut off the heater.

Dan

On Wed, 29 Jan 2014 08:21:33 -0800 (PST), "
wrote:

On Wednesday, January 29, 2014 9:13:12 AM UTC-5, robobass wrote:


You shouldn't have a saw and heater on the same line, anyway. It's no



wonder you're blowing breakers.



Agreed. No choice at the moment. Only one line.

When the motor is running, it is putting heat into the building, so you do not need the heater when using the saw. _So you could add a relay activated by turning on the saw. The relay would cut off the heater.

Dan
Greetings Dan,
It it was me I'd use your suggestion. Easy enough to wire. In fact,
contactors can be had with switches that turn off another contactor to
prevent plugging. When I put a new control on one of my mills I did
exactly this. And all the power coming from the motor does eventually
end up in the shop.
Eric


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On Wednesday, January 29, 2014 12:02:20 PM UTC-5, wrote:

It it was me I'd use your suggestion. And all the power coming from the motor does eventually

end up in the shop.

Eric


Many years ago, I suggested something similar. The Navy had a building with large electric heaters and a large air compressor. When both heaters and the air compressor were on, it exceeded the ratings of the transformers that supplied the building. The Navy just swapped out the power transformers for larger transformers.

Dan

On 29/01/14 14:04, robobass wrote:
Except that from the OPs other postings he is based in Germany and this

will be running off a single phase 230V supply not a US type centre

tapped style supply so the 110V to 120V changes have no bearing.

Correct.
AFAIK, we don't even do three phase here, just single phase 230 and 400. 400 is preferred for stoves and electric water and room heaters, which are common here since gas is more expensive than in US, but most older buildings don't have it. In my apartment building, we do central heat and hot water with a gas boiler in the cellar, but no gas to the units. Also interesting, most industrial machinery runs only on 400v, and the motors are rarely convertible. There is a lot of nonscientific thought here. I was warned to avoid a 230v lathe, even though it was only 750w. I was like..."your microwave oven (also distrusted here) sucks more power than that! What's wrong with running a lathe with 230v?"
You should enquire about 3 phase as a mate that used to live in Munich
said it was very common to have a 3 phase supply in a domestic house as
he did. Apparently rather than spread the phase loads between different
houses as is done in the UK, and I think the US, he said the different
floors were fed the different phases to balance the loads. Another who
posts here from time to time mentioned the same about 3 phase in houses
in Germany and was quite happy he could run a good sized 3phase welder
IIRC at home. My mothers old house in the UK had 3 phase because the
previous owner that built the house thought some of their garage units
could be used for light industrial use. They said the only additional
cost at the time was the 3 phase cable compared to single phase, no
problem getting it connected although it was never used the house only
had a single phase meter, at least the 3 phase was at the house if needed.

robobass wrote:


Thanks everyone for all the advice. To clarify, it's a 16 amp breaker,
230v. I haven't looked at it, but it's almost certainly not a special
"motor rated breaker". I'll try that first, as that would be quick and
cheap. I didn't realize until last night how big that motor was. In
principal I have 3.8kw on the circuit, which I have been abusing, running
about 3kw for heating and not always shutting that down before starting up
the saw. The box is close by, and it would be easy enough to run another
circuit or two to the shop, but the toilet guys are typical cautious
Germans and won't let me do it myself. Paying an electrician to do it
would naturally be expensive, but I suppose I'll have to bite the bullet
at some point. For now I just have to be diligent about managing my
current draw.
OK, this explains the problem! Note that most induction motors draw
a current close to the full rating even when idling. This current
is at a very lagging power factor, so the true wattage is small, but
the current is large. As the load is increased, the phase angle changes,
so greater wattage is drawn although the current reading only increases
slightly. The breaker only senses current, and not power.

So, your 14.5 Amp motor most likely draws about 12 A with the saw
idling, and could be 60+ Amps during the start. Obviously, you
can't run more than a small light bulb on the same circuit at the same
time without risking tripping that 16 A breaker. Especially if it is
a standard breaker, and not a motor-load breaker.

You may be able to do most of the work (drilling holes, installing
conduit, etc.) and then just have the licensed electrician make the
final connection. You might save some money that way.

Jon

On 29 Jan 2014 05:48:04 GMT, "DoN. Nichols"
wrote:

On 2014-01-29, wrote:
On Tue, 28 Jan 2014 13:47:51 -0600, Jon Elson
wrote:

robobass wrote:

I have a Sheppach table saw which constantly blows the fuse on startup. On
the motor it says 14.5 amps at 230 volts, which I interpret to be about 4
1/2 horsepower. I share my power with a bathroom fixtures supplier, and

[ ... ]

Jon
If it is 4HP there is a very STRONG chance it can be re-jumpered for
240 volts. I had the same problem with my compressor - 240 fixed it.

He is *already* running at 230 VAC which is just another way of
saying 240 VAC these days. Normal outlet voltage has been changing over
the years. I remember some equipment rated at 110 V, then 115 V, then
117 V, and now 120 V. 230/240 is simply double whichever voltage is the
current one.

And 14.5 A is pretty high for an outlet-connected motor, and
would be certain to pop a 15A breaker. If the wiring is heavy-duty, he
may have 20A braker and outlets. But a motor rated breaker, with the
curve which allows longer/higher start-up currents while working at the
normal current for really long-term power drains..

Enjoy,
DoN.
I missed the 230 volt reference - What amperage circuit is he on???
Virtually never see 15 amp 240 around here - very occaisionally see
20, more commonly 30.

On Wed, 29 Jan 2014 02:44:10 -0800 (PST), robobass
wrote:


Thanks everyone for all the advice. To clarify, it's a 16 amp breaker, 230v. I haven't looked at it, but it's almost certainly not a special "motor rated breaker". I'll try that first, as that would be quick and cheap. I didn't realize until last night how big that motor was. In principal I have 3.8kw on the circuit, which I have been abusing, running about 3kw for heating and not always shutting that down before starting up the saw. The box is close by, and it would be easy enough to run another circuit or two to the shop, but the toilet guys are typical cautious Germans and won't let me do it myself. Paying an electrician to do it would naturally be expensive, but I suppose I'll have to bite the bullet at some point. For now I just have to be diligent about managing my current draw.

I take it this is a european setup?? Or british? Never see "16 amp"
breakers in North America. If so, it is line to neutral, not line to
line like here in the Americas. Get a SPDT switch or contactor and
wire it so the saw and the heater can NEVER be on at the same time..

On Wed, 29 Jan 2014 06:04:29 -0800 (PST), robobass
wrote:



Except that from the OPs other postings he is based in Germany and this

will be running off a single phase 230V supply not a US type centre

tapped style supply so the 110V to 120V changes have no bearing.


Correct.
AFAIK, we don't even do three phase here, just single phase 230 and 400. 400 is preferred for stoves and electric water and room heaters, which are common here since gas is more expensive than in US, but most older buildings don't have it. In my apartment building, we do central heat and hot water with a gas boiler in the cellar, but no gas to the units. Also interesting, most industrial machinery runs only on 400v, and the motors are rarely convertible. There is a lot of nonscientific thought here. I was warned to avoid a 230v lathe, even though it was only 750w. I was like..."your microwave oven (also distrusted here) sucks more power than that! What's wrong with running a lathe with 230v?"
We run 10 inchers on 115 /120 over here.

robobass wrote:


Except that from the OPs other postings he is based in Germany and this

will be running off a single phase 230V supply not a US type centre

tapped style supply so the 110V to 120V changes have no bearing.


Correct.
AFAIK, we don't even do three phase here, just single phase 230 and 400. 400 is preferred for stoves and electric water and room heaters, which are common here since gas is more expensive than in US, but most older buildings don't have it. In my apartment building, we do central heat and hot water with a gas boiler in the cellar, but no gas to the units. Also interesting, most industrial machinery runs only on 400v, and the motors are rarely convertible. There is a lot of nonscientific thought here. I was warned to avoid a 230v lathe, even though it was only 750w. I was like..."your microwave oven (also distrusted here) sucks more power than that! What's wrong with running a lathe with 230v?"

I have a large Milwaukee grinder that pops a 20 amp breaker. To use it
I have to put a extension cord in series with the grinder. Also the
cord has to be a thin one to cut down on the starting current. The
breaker is brand new and this happens on several different circuits.

John

robobass wrote:

Ask if you could do the work yourself and then let the electrician

connect it all up for you. That'll save you a lot of money. Find an

electrician who'll do it for you, then check with the store owners.

Yes, that's the plan. It will still be expensive though. These guys here are insane, and people put up with it.


You shouldn't have a saw and heater on the same line, anyway. It's no

wonder you're blowing breakers.

Agreed. No choice at the moment. Only one line.

Try putting an extension cord in series with the machine. There will be
enough current limiting with a light duty cord.

John

On 1/29/2014 5:43 PM, wrote:

...
Virtually never see 15 amp 240 around here - very occaisionally see
20, more commonly 30.

My well/pump and my drill press/lathe/mill VFDs are on 15A 240 circuits.
They're common enough that HD/Lowes carries them. My "here" being
Massachusetts. Bob

Thanks for more suggestions. Yes, I'm in Germany where your standard box has 16 amp breakers and 230v, line and neutral. Many newer houses and buildings also have 1 phase 400v, which is mainly used for instantaneous water heaters (which I hate!). There may be three phase some places, but I've never seen it.

As for my problem, I'm surprised I'm not having more trouble than I am. I don't think I've ever blown the breaker when starting the table saw if the heaters are off, and it usually doesn't happen if only one heater is off. That means I'm pulling like 5.3KW!

Interesting the idea of running a long extension cord. I always thought that the opposite was true - that more copper, not less, is easier on the breaker. At any rate, I think I'm sort of doing that already. The wires are pretty thin - the space having been a garage before, where only lighting was expected. When I was running almost everything from one receptacle, and I noticed that the wire to it was getting warm. Now that I've spread things out that's no longer evident.

I think that I can get the guys to agree to let me do the runs for new circuits as long as I hire an electrician to connect everything up. That is what I'll do. In the mean time I just have to be diligent about shutting off the heaters when using the saw. I don't use it all that much anyway!

"robobass" wrote in message
...

Interesting the idea of running a long extension cord. I always
thought that the opposite was true - that more copper, not less, is
easier on the breaker. At any rate, I think I'm sort of doing that
already. The wires are pretty thin - the space having been a garage
before, where only lighting was expected. When I was running almost
everything from one receptacle, and I noticed that the wire to it was
getting warm. Now that I've spread things out that's no longer
evident.

Resistance in the wire prolongs the time the motor's start windings
are engaged, possibly enough to overheat them.

Resistance in the wire prolongs the time the motor's start windings

are engaged, possibly enough to overheat them.

There you have it. Don't underfeed your machines. They need clean, healthy amps, and lots of 'em!

On Thu, 30 Jan 2014 04:27:08 -0800 (PST), robobass
wrote:


Interesting the idea of running a long extension cord. I always thought that the opposite was true - that more copper, not less, is easier on the breaker. At any rate, I think I'm sort of doing that already. The wires are pretty thin - the space having been a garage before, where only lighting was expected. When I was running almost everything from one receptacle, and I noticed that the wire to it was getting warm. Now that I've spread things out that's no longer evident.


I think the guy who suggested that did so because it worked for him
with a big angle grinder. The grinder has a universal brush motor,
which is perfectly happy running on reduced voltage, and reduced power
output. Your saw presumably has an induction motor, which isn't nearly
as forgiving. It will likely draw more current at a lower voltage -
look at the nameplate on a 208-230/460 volt motor for a real-world
example:
http://www.arescobuyersclub.com/nameplates.html

--
Ned Simmons

On Thu, 30 Jan 2014 10:07:52 -0500, Ned Simmons
wrote:

On Thu, 30 Jan 2014 04:27:08 -0800 (PST), robobass
wrote:


Interesting the idea of running a long extension cord. I always thought that the opposite was true - that more copper, not less, is easier on the breaker. At any rate, I think I'm sort of doing that already. The wires are pretty thin - the space having been a garage before, where only lighting was expected. When I was running almost everything from one receptacle, and I noticed that the wire to it was getting warm. Now that I've spread things out that's no longer evident.


I think the guy who suggested that did so because it worked for him
with a big angle grinder. The grinder has a universal brush motor,
which is perfectly happy running on reduced voltage, and reduced power
output. Your saw presumably has an induction motor, which isn't nearly
as forgiving. It will likely draw more current at a lower voltage -
look at the nameplate on a 208-230/460 volt motor for a real-world
example:
http://www.arescobuyersclub.com/nameplates.html
No, in my case it was an old Beaver table saw with a 1hp Lehland
repulsion start induction motor (one that has brushes for starting)

On Thu, 30 Jan 2014 17:50:02 -0500, wrote:

On Thu, 30 Jan 2014 10:07:52 -0500, Ned Simmons
wrote:

On Thu, 30 Jan 2014 04:27:08 -0800 (PST), robobass
wrote:


Interesting the idea of running a long extension cord. I always thought that the opposite was true - that more copper, not less, is easier on the breaker. At any rate, I think I'm sort of doing that already. The wires are pretty thin - the space having been a garage before, where only lighting was expected. When I was running almost everything from one receptacle, and I noticed that the wire to it was getting warm. Now that I've spread things out that's no longer evident.


I think the guy who suggested that did so because it worked for him
with a big angle grinder. The grinder has a universal brush motor,
which is perfectly happy running on reduced voltage, and reduced power
output. Your saw presumably has an induction motor, which isn't nearly
as forgiving. It will likely draw more current at a lower voltage -
look at the nameplate on a 208-230/460 volt motor for a real-world
example:
http://www.arescobuyersclub.com/nameplates.html
No, in my case it was an old Beaver table saw with a 1hp Lehland
repulsion start induction motor (one that has brushes for starting)

The post I had in mind said, "I have a large Milwaukee grinder that
pops a 20 amp breaker. To use it I have to put a extension cord in
series with the grinder."

Because the start-up surge for a repulsion start/induction run motor
is smaller than for a straight induction motor, I've heard they were
often used in rural areas with long or marginal capacity feeds, much
like an undersized extension.

But, once up to speed, I'd expect a repulsion/induction motor to draw
more current as the voltage sags, just like a regular induction motor.
Maybe that's part of the reason, besides added complexity, they're
typically so big - so they'll tolerate undervoltage and the resulting
higher current.

My compressor has a 5HP repulsion start/induction run motor on it
that's bigger than a modern 15HP motor. It's strapped for 230V, but
can be reconnected for 115V.

--
Ned Simmons

On Thu, 30 Jan 2014 18:38:40 -0500, Ned Simmons
wrote:

On Thu, 30 Jan 2014 17:50:02 -0500, wrote:

On Thu, 30 Jan 2014 10:07:52 -0500, Ned Simmons
wrote:

On Thu, 30 Jan 2014 04:27:08 -0800 (PST), robobass
wrote:


Interesting the idea of running a long extension cord. I always thought that the opposite was true - that more copper, not less, is easier on the breaker. At any rate, I think I'm sort of doing that already. The wires are pretty thin - the space having been a garage before, where only lighting was expected. When I was running almost everything from one receptacle, and I noticed that the wire to it was getting warm. Now that I've spread things out that's no longer evident.


I think the guy who suggested that did so because it worked for him
with a big angle grinder. The grinder has a universal brush motor,
which is perfectly happy running on reduced voltage, and reduced power
output. Your saw presumably has an induction motor, which isn't nearly
as forgiving. It will likely draw more current at a lower voltage -
look at the nameplate on a 208-230/460 volt motor for a real-world
example:
http://www.arescobuyersclub.com/nameplates.html
No, in my case it was an old Beaver table saw with a 1hp Lehland
repulsion start induction motor (one that has brushes for starting)

The post I had in mind said, "I have a large Milwaukee grinder that
pops a 20 amp breaker. To use it I have to put a extension cord in
series with the grinder."

Because the start-up surge for a repulsion start/induction run motor
is smaller than for a straight induction motor, I've heard they were
often used in rural areas with long or marginal capacity feeds, much
like an undersized extension.

But, once up to speed, I'd expect a repulsion/induction motor to draw
more current as the voltage sags, just like a regular induction motor.
Maybe that's part of the reason, besides added complexity, they're
typically so big - so they'll tolerate undervoltage and the resulting
higher current.

My compressor has a 5HP repulsion start/induction run motor on it
that's bigger than a modern 15HP motor. It's strapped for 230V, but
can be reconnected for 115V.
We always used repulsion start motors on the bale elevators on the
farm, They could start with a load of bales - a 2 HP would start a
heavier load than a 5 hp cap start.

On Sat, 01 Feb 2014 00:36:12 -0800, Gunner Asch
wrote:

On 29 Jan 2014 05:48:04 GMT, "DoN. Nichols"
wrote:

On 2014-01-29, wrote:
On Tue, 28 Jan 2014 13:47:51 -0600, Jon Elson
wrote:

robobass wrote:

I have a Sheppach table saw which constantly blows the fuse on startup. On
the motor it says 14.5 amps at 230 volts, which I interpret to be about 4
1/2 horsepower. I share my power with a bathroom fixtures supplier, and

[ ... ]

Jon
If it is 4HP there is a very STRONG chance it can be re-jumpered for
240 volts. I had the same problem with my compressor - 240 fixed it.

He is *already* running at 230 VAC which is just another way of
saying 240 VAC these days. Normal outlet voltage has been changing over
the years. I remember some equipment rated at 110 V, then 115 V, then
117 V, and now 120 V. 230/240 is simply double whichever voltage is the
current one.

And 14.5 A is pretty high for an outlet-connected motor, and
would be certain to pop a 15A breaker. If the wiring is heavy-duty, he
may have 20A braker and outlets. But a motor rated breaker, with the
curve which allows longer/higher start-up currents while working at the
normal current for really long-term power drains..

Enjoy,
DoN.

A LOT of Euro and Asian gear goes 200-208. US tends to be 208-220, and
only the newer stuff runs 230-240.

He certainly needs at minimum a 20 amp breaker no matter what.

TWO. One for the heaters, one for the saw.


--
I have the consolation of having added nothing to my private fortune during
my public service, and of retiring with hands clean as they are empty.
-- Thomas Jefferson, letter to Count Diodati, 1807

Too bad -none- of the current CONgresscritters are willing to do that. -LJ

A LOT of Euro and Asian gear goes 200-208. US tends to be 208-220, and

only the newer stuff runs 230-240.

Most Euro power is 230v with 16 amp breakers.

He certainly needs at minimum a 20 amp breaker no matter what.



TWO. One for the heaters, one for the saw.

Two would be nice, three better. One for heating, a second for the saw, and a third for everything else.

I've discovered that 3 phase is actually common in Germany, but it's different. Since each leg is 230v to neutral, then I presume that between legs it is around 460v. So, normally you don't have any two legs coming anywhere near each other. In a private house you might be able to access 3 ph. but not in a building, unless you want to pay for some expensive electrical work.

In my case, I'm running power from a secondary box in the courtyard behind the main building. That's almost certainly only 1 ph. I can add a couple circuits from there, but I wonder if the box itself can handle the draw. The idea of a cutout relay on the heaters now looks worth exploring.

As things stand, it's only the combination of the saw and heaters which is creating problems. With the heaters running, I can still run the lathe, lights, and small machines without trouble, so at the moment there's no need to load up a trebuchet with stacks of Euro notes to attack this inconvenience!