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Default Lights dim with swamp cooler.

Hi, we recently installed a window version of a swamp cooler. As such, it plugs into a wall outlet in the lounge-room. It has a new 1/3-hp (252-Watt) two speed motor from HomeDepot.

When it turns on either in Low or High, the voltage dips for almost a second from 125vac to 117vac then back up to 125vac. The dimming is maybe 20% longer for the High speed.

Is there some way we can soft-start this or what? It makes the lights dim in the house for that short period.

Before anyone launches into "house wiring," etc rest assured it is 11-years old, copper, in metal conduits and all up to code with 200-Amp coming into the house.

I used a 14g, 3-wire extension lead in a bunch of other outlets on different circuits and still get the same issue. I then hard wired the extension into the main breaker panel. Same again.

I have cleaned and oiled the fan bearings, adjusted the belt and the fan turns quite freely by hand.

What can be done to alleviate this momentary voltage drop?

Thanks
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Default Lights dim with swamp cooler.

On Tue, 11 Jul 2017 14:40:03 -0700 (PDT), "Dave, I can't do that"
wrote:

Hi, we recently installed a window version of a swamp cooler. As such, it plugs into a wall outlet in the lounge-room. It has a new 1/3-hp (252-Watt) two speed motor from HomeDepot.

When it turns on either in Low or High, the voltage dips for almost a second from 125vac to 117vac then back up to 125vac. The dimming is maybe 20% longer for the High speed.


What do the house lights do when you plug in a 1500W heater in that
outlet? Same thing, but worse? (reading on, never mind with this)


Is there some way we can soft-start this or what? It makes the lights dim in the house for that short period.


If you used LED or CFL lighting, you wouldn't see that.


Before anyone launches into "house wiring," etc rest assured it is 11-years old, copper, in metal conduits and all up to code with 200-Amp coming into the house.


14ga copper, right? Not the largest.


I used a 14g, 3-wire extension lead in a bunch of other outlets on different circuits and still get the same issue. I then hard wired the extension into the main breaker panel. Same again.


That little motor is drawing a whopper of a current during startup, it
seems. Inductive current draw is normal with motors.

Check with your electric company. Mine recently replaced the drop to
my house because it was old and worn and improperly terminated on the
house. If you have a feed with half the copper strands broken from
age, it -will- cause the drop you see, even at the breaker box. The
electric company usually pays for all wiring up to the meter/box.


I have cleaned and oiled the fan bearings, adjusted the belt and the fan turns quite freely by hand.

What can be done to alleviate this momentary voltage drop?


Unplug swamp cooler, R&R house. snort

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Default Lights dim with swamp cooler.

On Tue, 11 Jul 2017 14:40:03 -0700 (PDT), "Dave, I can't do that"
wrote:

Hi, we recently installed a window version of a swamp cooler. As such, it plugs into a wall outlet in the lounge-room. It has a new 1/3-hp (252-Watt) two speed motor from HomeDepot.

When it turns on either in Low or High, the voltage dips for almost a second from 125vac to 117vac then back up to 125vac. The dimming is maybe 20% longer for the High speed.

Is there some way we can soft-start this or what? It makes the lights dim in the house for that short period.

Before anyone launches into "house wiring," etc rest assured it is 11-years old, copper, in metal conduits and all up to code with 200-Amp coming into the house.

I used a 14g, 3-wire extension lead in a bunch of other outlets on different circuits and still get the same issue. I then hard wired the extension into the main breaker panel. Same again.

I have cleaned and oiled the fan bearings, adjusted the belt and the fan turns quite freely by hand.

What can be done to alleviate this momentary voltage drop?

Thanks

Since you hard wired the motor in the breaker panel did it get its own
breaker? I would be surprised if the voltage sagged that much if wire
directly to one leg of the 220 volts coming into the panel. Also since
you hard wired the thing is the motor perhaps a dual voltage motor? If
so changing it to 240 volts and using both legs of the incoming power
will make a big difference in the lights dimmimg. This is because the
dimming of incandescent lights is not linear with the drop in voltage.
A small voltage drop will result in a larger drop of visible light.
Induction motors can draw up to 6 times the running current when
starting. So the amperage draw can be quite high. Especially when the
motor is a crappy one. Lots of import motors are crummy motors. They
sometimes use less wire in the start windings which leads to lower
resistance and higher current draw. Soft start controllers are
available but can be expensive. Is the motor a capacitor start motor?
Maybe the cap is not up to snuff. Still, I'm surprised that if the
motor is wired to a 100 amp supply the voltage would sag that much if
nothing else is using the same leg of the incoming supply the same
time. What other loads are connected to the leg supplying the swamp
cooler motor?
Eric
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Default Lights dim with swamp cooler.

On 2017-07-11, Dave, I can't do that wrote:

Hi, we recently installed a window version of a swamp cooler. As such,
it plugs into a wall outlet in the lounge-room. It has a new 1/3-hp
(252-Watt) two speed motor from HomeDepot.


When it turns on either in Low or High, the voltage dips for almost a
second from 125vac to 117vac then back up to 125vac. The dimming is
maybe 20% longer for the High speed.


Still within specs. Why worry about it? Does anything
misbehave during those dips?

Is there some way we can soft-start this or what? It makes the lights
dim in the house for that short period.


With that motor -- maybe a loose belt to let it slip as it goes
up to speed?

For real soft start, replace it with a three-phase motor and a
VFD. You can program the VFD for a fairly wide range of starting times.

Enjoy,
DoN.

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Default Lights dim with swamp cooler.

On Tuesday, July 11, 2017 at 5:40:08 PM UTC-4, Dave, I can't do that wrote:


What can be done to alleviate this momentary voltage drop?

Thanks


Do you have a way to measure the current drawn by the motor? If you can measure the current , you can put some oil filled capacitors in parallel with the motor and find a combination that minimises the current. -In other words correct the power factor. This may or may not be enough to reduce the momentary voltage drop to a level that is acceptable. But will help.

Capacitors can be found in junk microwave ovens.

Dan


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Default Lights dim with swamp cooler.

Thanks Guys,

The power drop sometimes scrambled the tiny-brain of an Arduino temp-sensor I have running from the same outlet. It still does the same to the Temp sensor if I plug it into another outlet. I have some 10K-electro-caps coming for the Arduino 5vdc line, so that should stop that.

Other than that, the dimming is annoying to some members of the household.
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Default Lights dim with swamp cooler.

On Wednesday, July 12, 2017 at 7:41:43 AM UTC-7, wrote:

Do you have a way to measure the current drawn by the motor? If you can measure the current , you can put some oil filled capacitors in parallel with the motor and find a combination that minimises the current.


Thanks Dan,

Using a watt-meter thingy, on Low it draws about 5.1-A and on High 6.3-A. I say "about" as it fluctuates up/down by 0.1-A or so.

During the start, it very briefly shows 16-A or 17-A but there could be a little over-swing in that too. It comes and goes in the blink of an eye, sometimes I don't even see it at all.

So what do I actually need to do with the caps? I have some oil-filled start caps around the place somewhere.

This is the motor.
https://www.lowes.com/pd/Dial-Steel-...-Motor/1016109
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Default Lights dim with swamp cooler.

"Dave, I can't do that" wrote in message
...
Thanks Guys,

The power drop sometimes scrambled the tiny-brain of an Arduino
temp-sensor I have running from the same outlet. It still does the
same to the Temp sensor if I plug it into another outlet. I have some
10K-electro-caps coming for the Arduino 5vdc line, so that should stop
that.

Other than that, the dimming is annoying to some members of the
household.

==================

Do you have large resistive loads like space heaters, toasters or
coffee pots that you could use to trace the steady-state drop? The
problem might be the cable connections in the panel or the meter box.

I had a problem with a poor connection to neutral, which caused the
two 'phases' to unbalance when a motor started. Some lights dimmed,
others flashed brighter. The power company cured it by replacing the
meter box and weatherhead cable. They knew the old aluminum splices
tended to corrode.

-jsw


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Default Lights dim with swamp cooler.

On Wednesday, July 12, 2017 at 11:09:30 AM UTC-4, Dave, I can't do that wrote:

Using a watt-meter thingy, on Low it draws about 5.1-A and on High 6.3-A. I say "about" as it fluctuates up/down by 0.1-A or so.

During the start, it very briefly shows 16-A or 17-A but there could be a little over-swing in that too. It comes and goes in the blink of an eye, sometimes I don't even see it at all.

So what do I actually need to do with the caps? I have some oil-filled start caps around the place somewhere.


The motor is a 1/3 hp motor. One hp is 746 watts so 1/3 hp is 249 watts.. and 249 divided by 120 volts is just over 2 amps. So of the 5 amps on low speed 2 amps is the real power drawn and about 4.6 is the imaginary amps..

Putting caps in parallel with the motor will reduce the imaginary current. It is pointless to get rid of all the imaginary current. But try putting a cap across in parallel with the motor and see what the current is. Add more caps until the current is down to about 2.5 amps instead of 5. And see if that helps to reduce the light dimming. It will help , but may not be a noticeable change.

Dan

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Default Lights dim with swamp cooler.

On Tuesday, July 11, 2017 at 5:40:08 PM UTC-4, Dave, I can't do that wrote:
Hi, we recently installed a window version of a swamp cooler. As such, it plugs into a wall outlet in the lounge-room. It has a new 1/3-hp (252-Watt) two speed motor from HomeDepot.

When it turns on either in Low or High, the voltage dips for almost a second from 125vac to 117vac then back up to 125vac. The dimming is maybe 20% longer for the High speed.

Is there some way we can soft-start this or what? It makes the lights dim in the house for that short period.

Before anyone launches into "house wiring," etc rest assured it is 11-years old, copper, in metal conduits and all up to code with 200-Amp coming into the house.

I used a 14g, 3-wire extension lead in a bunch of other outlets on different circuits and still get the same issue. I then hard wired the extension into the main breaker panel. Same again.

I have cleaned and oiled the fan bearings, adjusted the belt and the fan turns quite freely by hand.

What can be done to alleviate this momentary voltage drop?

Thanks


First, 117V is well within specs. That said, a 1/3 HP motor shouldn't load down your system like that. There is likely either a defective feed cable or a loose connection from the utility. You could check in the panel to make sure the feed cables are tight. Beyond that, you'll have to get the utility company to check it out. Around here, at least, they're usually pretty cooperative.


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Default Lights dim with swamp cooler.

On Wed, 12 Jul 2017 11:47:11 -0400, "Jim Wilkins"
wrote:

"Dave, I can't do that" wrote in message
...
Thanks Guys,

The power drop sometimes scrambled the tiny-brain of an Arduino
temp-sensor I have running from the same outlet. It still does the
same to the Temp sensor if I plug it into another outlet. I have some
10K-electro-caps coming for the Arduino 5vdc line, so that should stop
that.

Other than that, the dimming is annoying to some members of the
household.

==================

Do you have large resistive loads like space heaters, toasters or
coffee pots that you could use to trace the steady-state drop? The
problem might be the cable connections in the panel or the meter box.

I had a problem with a poor connection to neutral, which caused the
two 'phases' to unbalance when a motor started. Some lights dimmed,
others flashed brighter. The power company cured it by replacing the
meter box and weatherhead cable. They knew the old aluminum splices
tended to corrode.

-jsw

I recently had to replace the entire breaker panel at the beach condo.
The original aluminum bus bars were corroded, and burned on some high
amp breakers. We had several appliance board failures before we
figured it out. It was also exacerbated by voltage swings due to the
utility replacing all the feeders down the island.

The original breaker panel had paint and texture sprayed on the
interior, and had probably been soaked in salt water during Ike
because the original builder not only went cheap on the panels, but
some of the patio soffits were sheetrock instead of hardie board,
causing disintegration and much wind blown water damage to all units.
The new ones are copper.

Pete Keillor
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Default Lights dim with swamp cooler.

Dave, I can't do that wrote:

On Wednesday, July 12, 2017 at 7:41:43 AM UTC-7, wrote:

Do you have a way to measure the current drawn by the motor? If you can
measure the current , you can put some oil filled capacitors in parallel
with the motor and find a combination that minimises the current.


Thanks Dan,

Using a watt-meter thingy, on Low it draws about 5.1-A and on High 6.3-A.
I say "about" as it fluctuates up/down by 0.1-A or so.

During the start, it very briefly shows 16-A or 17-A but there could be a
little over-swing in that too. It comes and goes in the blink of an eye,
sometimes I don't even see it at all.

Well, if you still get the dip at other outlets when the cooler is wried
into the breaker panel, you may have copper creep on the terminals in the
panel or the meter box. That is dangerous stuff to work on, so you might
want to have an electrician do it (capability to deliver high fault
currents).

I have re-torqued the clamp screws on the breakers where the branch circuit
wires connect, so you can try doing that. I have occasionally found some of
these to be quite loose.

Jon
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Default Lights dim with swamp cooler.

In article ,
Dave, I can't do that writes
Hi, we recently installed a window version of a swamp cooler. As such, it plugs
into a wall outlet in the lounge-room. It has a new 1/3-hp (252-Watt) two speed
motor from HomeDepot.

When it turns on either in Low or High, the voltage dips for almost a second
from 125vac to 117vac then back up to 125vac. The dimming is maybe 20% longer
for the High speed.

Is there some way we can soft-start this or what? It makes the lights dim in the
house for that short period.

Before anyone launches into "house wiring," etc rest assured it is 11-years old,
copper, in metal conduits and all up to code with 200-Amp coming into the house.

I used a 14g, 3-wire extension lead in a bunch of other outlets on different
circuits and still get the same issue. I then hard wired the extension into the
main breaker panel. Same again.

I have cleaned and oiled the fan bearings, adjusted the belt and the fan turns
quite freely by hand.

What can be done to alleviate this momentary voltage drop?

Thanks

I wonder if a suitable thermistor (ntc), wired in series with the motor
would do the job simply and cheaply? E.g. EPCOS B57127P0109M301
--
Chris Holford
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Default Lights dim with swamp cooler.

On 2017-07-12, wrote:
On Tuesday, July 11, 2017 at 5:40:08 PM UTC-4, Dave, I can't do that wrote:


What can be done to alleviate this momentary voltage drop?

Thanks


Do you have a way to measure the current drawn by the motor? If you
can measure the current , you can put some oil filled capacitors in
parallel with the motor and find a combination that minimises the
current. -In other words correct the power factor. This may or may not
be enough to reduce the momentary voltage drop to a level that is
acceptable. But will help.


The primary problem is while the start winding is engaged, so it
would have to be added to the internal wiring in parallel with the start
winding. Add a second "bump" to house an oil-filled AC-rated capacitor.
(And *don't* use motor starting caps -- they are only for short power
application -- and they might stretch the starting time enough to be a
problem both for the starting cap and the phase correction cap.

The best way to tune that value would be with the run winding
disconnected, and something keeping the motor from turning -- and just
short tests each time to keep the start winding from overheating.

Yes, it is easier to simply compensate the run winding, but that
won't eliminate the voltage sag on starting.

Capacitors can be found in junk microwave ovens.


Yep -- or as run caps for motors for squirrel cage blowers in
HVAC units.

Or -- you can get one of the universal substitute run caps for
the AC compressor -- Turbo 200 from Amrad Engineering. It has six
different values of capacitors, connected together at a central common
terminal, and jumpers (push-on connectors) to add them in parallel. The
values, between them, offer a fairly wide range of possible values.
Cap values add in parallel, while resistor values add in series.
Anyway, this gives you a single device to use to try a number of values.

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 ---
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Default Lights dim with swamp cooler.

On Wed, 12 Jul 2017 22:30:06 +0100, Chris Holford
wrote:

In article ,
Dave, I can't do that writes
Hi, we recently installed a window version of a swamp cooler. As such, it plugs
into a wall outlet in the lounge-room. It has a new 1/3-hp (252-Watt) two speed
motor from HomeDepot.

When it turns on either in Low or High, the voltage dips for almost a second
from 125vac to 117vac then back up to 125vac. The dimming is maybe 20% longer
for the High speed.

Is there some way we can soft-start this or what? It makes the lights dim in the
house for that short period.

Before anyone launches into "house wiring," etc rest assured it is 11-years old,
copper, in metal conduits and all up to code with 200-Amp coming into the house.

I used a 14g, 3-wire extension lead in a bunch of other outlets on different
circuits and still get the same issue. I then hard wired the extension into the
main breaker panel. Same again.

I have cleaned and oiled the fan bearings, adjusted the belt and the fan turns
quite freely by hand.

What can be done to alleviate this momentary voltage drop?

Thanks

I wonder if a suitable thermistor (ntc), wired in series with the motor
would do the job simply and cheaply? E.g. EPCOS B57127P0109M301

I think it is a pretty sure bet he has a problem with the electrical
service to the home - either in the panel. the meter box, or the wires
to the house. He needs a good professional electrician to verify it
and either repair it or get the electrical service provider to fix
it.


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Default Lights dim with swamp cooler.

On 2017-07-12, Dave, I can't do that wrote:
On Wednesday, July 12, 2017 at 7:41:43 AM UTC-7, wrote:


Do you have a way to measure the current drawn by the motor? If you
can measure the current , you can put some oil filled capacitors in
parallel with the motor and find a combination that minimises the
current.


Thanks Dan,


Using a watt-meter thingy, on Low it draws about 5.1-A and on High
6.3-A. I say "about" as it fluctuates up/down by 0.1-A or so.


So a digital readout -- common for the LSD (Least Significant
Digit) to display some uncertainty.

Is this by any chance a Kill-a-Watt?

During the start, it very briefly shows 16-A or 17-A but there could
be a little over-swing in that too. It comes and goes in the blink of an
eye, sometimes I don't even see it at all.


Without a physical meter needle, it is unlikely that there will
be overshoot, and it is more likely that it will be a bit lower than the
actual peak value.

So what do I actually need to do with the caps? I have some oil-filled
start caps around the place somewhere.


Well ... if the actual high current peak is that brief, it may
be that compensating just the run winding will help. No need for a
separate compensation cap setup for the start winding.

Just connect them in parallel with the AC into the motor, and
adjust for minimum running current by adding values in parallel until
you get the lowest value.

This is the motor.
https://www.lowes.com/pd/Dial-Steel-...-Motor/1016109


Kind of skimpy information. Yes, complete copper windings, but
perhaps not enough iron in the core. How much does it weigh? That is a
good quick way to compare motors of the same horsepower rating.

And there is no suggestion that it could be re-wired for 240 VAC
instead of 120 VAC, which as someone else suggested, would reduce the
current drain -- as I did with the 1.5 HP motor on my 12" lathe.

Good Luck,
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 ---
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Default Lights dim with swamp cooler.

On Wed, 12 Jul 2017 20:13:20 -0400, wrote:

On Wed, 12 Jul 2017 22:30:06 +0100, Chris Holford
wrote:

In article ,
Dave, I can't do that writes
Hi, we recently installed a window version of a swamp cooler. As such, it plugs
into a wall outlet in the lounge-room. It has a new 1/3-hp (252-Watt) two speed
motor from HomeDepot.

When it turns on either in Low or High, the voltage dips for almost a second
from 125vac to 117vac then back up to 125vac. The dimming is maybe 20% longer
for the High speed.

Is there some way we can soft-start this or what? It makes the lights dim in the
house for that short period.

Before anyone launches into "house wiring," etc rest assured it is 11-years old,
copper, in metal conduits and all up to code with 200-Amp coming into the house.

I used a 14g, 3-wire extension lead in a bunch of other outlets on different
circuits and still get the same issue. I then hard wired the extension into the
main breaker panel. Same again.

I have cleaned and oiled the fan bearings, adjusted the belt and the fan turns
quite freely by hand.

What can be done to alleviate this momentary voltage drop?

Thanks

I wonder if a suitable thermistor (ntc), wired in series with the motor
would do the job simply and cheaply? E.g. EPCOS B57127P0109M301

I think it is a pretty sure bet he has a problem with the electrical
service to the home - either in the panel. the meter box, or the wires
to the house. He needs a good professional electrician to verify it
and either repair it or get the electrical service provider to fix
it.

I think you are absolutely right Clare. It just doesn't make sense to
me that this small motor connected directly to its own breaker in a
breaker panel could cause so much voltage sag. There must be a bad
connection somewhere. In my shop with a 200 amp service the 15HP motor
that's connected across both legs doesn't cause this kind of voltage
sag when it starts.
Eric
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Default Lights dim with swamp cooler.

On Tue, 11 Jul 2017 14:40:03 -0700 (PDT), "Dave, I can't do that"
wrote:

Hi, we recently installed a window version of a swamp cooler. As such, it plugs into a wall
outlet in the lounge-room. It has a new 1/3-hp (252-Watt) two speed motor from HomeDepot.

When it turns on either in Low or High, the voltage dips for almost a second from
125vac to 117vac then back up to 125vac. The dimming is maybe 20% longer for the High speed.

Is there some way we can soft-start this or what? It makes the lights dim in
the house for that short period.


The problem is the motor. The type of motor sold at H-D is designed
for low inertia loads that start very rapidly. This type of motor
draws tremendous starting current - I've seen as high as 80 amps - and
at low power factor.

The correct solution is to buy a fan duty motor. This type of motor
is designed for high inertia loads and is designed to draw only
moderate starting current. Your best bet would be to return that
motor if you can and buy the correct one from an electric motor shop.
If there isn't a shop near you, I recommend the shop where I used to
moon-light - Jerry's Electric Motor Shop, Cleveland, TN. 423
472-5959. Tell Jerry that I referred you.

If you're stuck with that motor, there are some things that you can
do. Foremost is to supply the starting current from a capacitor. The
starting current is very low lagging power factor. A motor start
capacitor will supply the leading power factor current to offset the
motor's lagging current demand so that mostly only real power (low
amps) is drawn from the line. The capacitor is simply connected in
parallel with the motor's terminals through a current relay.

The capacitor can't be left in the circuit. IT must be disconnected
once the current draw has dropped sufficiently. This is normally done
with a current mode starting relay.

This type of relay is normally open with a few heavy turns of wire as
the coil. The motor current flows through it AFTER the capacitor. The
contacts are connected in series with the motor start capacitor. The
inrush current draws in the relay, allowing the capacitor to supply
the imaginary power. When the current drops to say, 15 amp, the relay
drops out, disconnecting the capacitor.

If you're interested in tackling this kind of work, I can spec out the
components.

John
John DeArmond
http://www.neon-john.com
http://www.tnduction.com
Tellico Plains, Occupied TN
See website for email address

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Default Lights dim with swamp cooler.

On Wed, 12 Jul 2017 07:41:11 -0700 (PDT), "
wrote:

On Tuesday, July 11, 2017 at 5:40:08 PM UTC-4, Dave, I can't do that wrote:


What can be done to alleviate this momentary voltage drop?

Thanks


Do you have a way to measure the current drawn by the motor? If you can measure the current ,
you can put some oil filled capacitors in parallel with the motor and find a combination that
minimises the current. -In other words correct the power factor.
This may or may not be enough to reduce the momentary voltage drop to a
level that is acceptable. But will help.


No. The run power factor, what one would be correcting with a
capacitor left in place, would make only a small dent in the start-up
draw.

The difference is the size cap required. A typical run cap for that
size motor would be 5 uF. A start capacitor is an unpolarized
electrolytic and would be in the 300 uF range.

Capacitors can be found in junk microwave ovens.


Again, no. Microwave caps look the same but are of high voltage and
low capacity. Typically 5uF at 2500-4000 volts.

No need prowling through scrap to get a cap. New ones are quite
inexpensive.

John
John DeArmond
http://www.neon-john.com
http://www.tnduction.com
Tellico Plains, Occupied TN
See website for email address

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Default Lights dim with swamp cooler.

On Wed, 12 Jul 2017 08:09:24 -0700 (PDT), "Dave, I can't do that"
wrote:

Using a watt-meter thingy, on Low it draws about 5.1-A and on High 6.3-A. I say "about"
as it fluctuates up/down by 0.1-A or so.

During the start, it very briefly shows 16-A or 17-A but there could be a little over-swing in that too.
It comes and goes in the blink of an eye, sometimes I don't even see it at all.

So what do I actually need to do with the caps? I have some
oil-filled start caps around the place somewhere.

This is the motor.
https://www.lowes.com/pd/Dial-Steel-...-Motor/1016109


Based on knowing what actual motor you have, I'll modify my previous
post just a little.

This is a fan-duty motor but it is a very low quality motor, as one of
the Lowe's commenters noted.

A 1/3 motor should draw 746 watts * 0.33333. = 249 watts real power.

That translates to 249 watts / 120 volts = 2 amps. This is the real
power the motor is drawing to do the useful work of turning the fan.
The rest of the (let's average) 6 amps is "wattless" or imaginary
current. The power factor is 2 real amps / 6 total amps = a power
factor of 0.35. This is extremely poor. A quality motor when fully
loaded will have a power factor of 0.90 or better. As the commenter
noted, this is from the motor having little iron and copper inside it.
Basically, a cheap chicom substitute.

Since this is a fan-duty motor, it probably draws about 6X running
current while starting. So 6 running amp * 6 = 36 starting amps.

That much current load, applied suddenly, will cause lamp flicker.

This flicker will be exacerbated if you have an inadequately sized
pole pig (transformer) or more commonly, an undersized drop from the
utility.

I fought my utility for a long time over this issue. When we built
this cabin in 1970, it received a 100 amp box. About 10 years ago we
installed a heat pump and a 200 amp box. Severe light flickering
happened each time the heat pump started.

I traced the cause to the service drop being only 4 gauge aluminum
wire, severely undersized for a 200 amp panel.

I spent about half my life as a utility engineer so I could take on
the engineer at the utility. I provided him hard measured evidence of
the voltage drop but he ultimately refused to order a larger drop.

So I cut a tree down across the line and pulled it down.

The replacement drop is #0 gauge (still too small) and I still get a
bit of flicker but not nearly so bad as before. The primary feeding
our little mountain community is 25 miles long and is only 7200 volts
so some sag is happening on the utility side.

So you need to take a look at your service drop and see if you can
tell if it's too small. If you have a digital volt meter that has a
high/low peak reading function, you can connect it between neutral and
an otherwise unused breaker in your panel and record the voltage dip
at your service entrance when you start the swamp cooler. If the dip
at the panel is much over 3 volts, your drop and perhaps pole pig is
undersized.

A study years ago determined that the average person could detect the
flicker in a tungsten lamp at a 3 volt threshold. Electronic lights
(CFLs and LEDs) are even worse because there is no thermal inertia.

So my revised advice would be: a) determine whether your utility
service is adequate, b) take that motor back and buy a quality
name-brand motor such as GE or Emerson and only after that pursue what
I described in my previous post regarding fixing the inrush and power
factor problem.

You asked in your first post if the motor could be soft-started. The
answer is yes. Soft starters are available but most use a 3 phase
motor (single phase to the soft starter). A quality (non-chicom) soft
starter will cost several hundred dollars so I recommend the other
things first.

John
John DeArmond
http://www.neon-john.com
http://www.tnduction.com
Tellico Plains, Occupied TN
See website for email address



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Default Lights dim with swamp cooler.

"Neon John" wrote in message
...
On Tue, 11 Jul 2017 14:40:03 -0700 (PDT), "Dave, I can't do that"
wrote:

Hi, we recently installed a window version of a swamp cooler. As
such, it plugs into a wall
outlet in the lounge-room. It has a new 1/3-hp (252-Watt) two speed
motor from HomeDepot.

When it turns on either in Low or High, the voltage dips for almost
a second from
125vac to 117vac then back up to 125vac. The dimming is maybe 20%
longer for the High speed.

Is there some way we can soft-start this or what? It makes the
lights dim in
the house for that short period.


The problem is the motor. The type of motor sold at H-D is designed
for low inertia loads that start very rapidly. This type of motor
draws tremendous starting current - I've seen as high as 80 amps -
and
at low power factor.

The correct solution is to buy a fan duty motor. This type of motor
is designed for high inertia loads and is designed to draw only
moderate starting current. Your best bet would be to return that
motor if you can and buy the correct one from an electric motor
shop.
If there isn't a shop near you, I recommend the shop where I used to
moon-light - Jerry's Electric Motor Shop, Cleveland, TN. 423
472-5959. Tell Jerry that I referred you.

If you're stuck with that motor, there are some things that you can
do. Foremost is to supply the starting current from a capacitor.
The
starting current is very low lagging power factor. A motor start
capacitor will supply the leading power factor current to offset the
motor's lagging current demand so that mostly only real power (low
amps) is drawn from the line. The capacitor is simply connected in
parallel with the motor's terminals through a current relay.

The capacitor can't be left in the circuit. IT must be disconnected
once the current draw has dropped sufficiently. This is normally
done
with a current mode starting relay.

This type of relay is normally open with a few heavy turns of wire
as
the coil. The motor current flows through it AFTER the capacitor.
The
contacts are connected in series with the motor start capacitor. The
inrush current draws in the relay, allowing the capacitor to supply
the imaginary power. When the current drops to say, 15 amp, the
relay
drops out, disconnecting the capacitor.

If you're interested in tackling this kind of work, I can spec out
the
components.

John
John DeArmond
http://www.neon-john.com
http://www.tnduction.com
Tellico Plains, Occupied TN
See website for email address


I've only worked on older motors that I could take apart easily, most
recently a 1970ish Maytag with a broken connection to the start
winding. On it I could have connected a cap directly across the start
winding, after the centrifugal start switch. Is that generally
possible with newer consumer-grade motors?
-jsw


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Default Lights dim with swamp cooler.

On Thu, 13 Jul 2017 08:55:00 -0700, wrote:

On Wed, 12 Jul 2017 20:13:20 -0400,
wrote:

On Wed, 12 Jul 2017 22:30:06 +0100, Chris Holford
wrote:

In article ,
Dave, I can't do that writes
Hi, we recently installed a window version of a swamp cooler. As such, it plugs
into a wall outlet in the lounge-room. It has a new 1/3-hp (252-Watt) two speed
motor from HomeDepot.

When it turns on either in Low or High, the voltage dips for almost a second
from 125vac to 117vac then back up to 125vac. The dimming is maybe 20% longer
for the High speed.

Is there some way we can soft-start this or what? It makes the lights dim in the
house for that short period.

Before anyone launches into "house wiring," etc rest assured it is 11-years old,
copper, in metal conduits and all up to code with 200-Amp coming into the house.

I used a 14g, 3-wire extension lead in a bunch of other outlets on different
circuits and still get the same issue. I then hard wired the extension into the
main breaker panel. Same again.

I have cleaned and oiled the fan bearings, adjusted the belt and the fan turns
quite freely by hand.

What can be done to alleviate this momentary voltage drop?

Thanks
I wonder if a suitable thermistor (ntc), wired in series with the motor
would do the job simply and cheaply? E.g. EPCOS B57127P0109M301

I think it is a pretty sure bet he has a problem with the electrical
service to the home - either in the panel. the meter box, or the wires
to the house. He needs a good professional electrician to verify it
and either repair it or get the electrical service provider to fix
it.

I think you are absolutely right Clare. It just doesn't make sense to
me that this small motor connected directly to its own breaker in a
breaker panel could cause so much voltage sag. There must be a bad
connection somewhere. In my shop with a 200 amp service the 15HP motor
that's connected across both legs doesn't cause this kind of voltage
sag when it starts.
Eric

I have a 125 amp service, and rhere is NOTHING that causes lights to
dom - not the drier, the central air, the central vac, - NOTHING since
my meter base and panel were replaced. Before the new service went in,
"occaisionally" I'd get a bit of dimming when the AC cut in. A few
years ago I'd get some lights getting brighter and some dimmer when
the central vac was started, so I tightened the neutral.Fixed that!!
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Default Lights dim with swamp cooler.

On Tue, 11 Jul 2017 17:53:47 -0700, wrote:

On Tue, 11 Jul 2017 14:40:03 -0700 (PDT), "Dave, I can't do that"
wrote:

Hi, we recently installed a window version of a swamp cooler. As such, it plugs into a wall outlet in the lounge-room. It has a new 1/3-hp (252-Watt) two speed motor from HomeDepot.

When it turns on either in Low or High, the voltage dips for almost a second from 125vac to 117vac then back up to 125vac. The dimming is maybe 20% longer for the High speed.

Is there some way we can soft-start this or what? It makes the lights dim in the house for that short period.

Before anyone launches into "house wiring," etc rest assured it is 11-years old, copper, in metal conduits and all up to code with 200-Amp coming into the house.

I used a 14g, 3-wire extension lead in a bunch of other outlets on different circuits and still get the same issue. I then hard wired the extension into the main breaker panel. Same again.

I have cleaned and oiled the fan bearings, adjusted the belt and the fan turns quite freely by hand.

What can be done to alleviate this momentary voltage drop?

Thanks

Since you hard wired the motor in the breaker panel did it get its own
breaker? I would be surprised if the voltage sagged that much if wire
directly to one leg of the 220 volts coming into the panel. Also since
you hard wired the thing is the motor perhaps a dual voltage motor? If
so changing it to 240 volts and using both legs of the incoming power
will make a big difference in the lights dimmimg. This is because the
dimming of incandescent lights is not linear with the drop in voltage.
A small voltage drop will result in a larger drop of visible light.
Induction motors can draw up to 6 times the running current when
starting. So the amperage draw can be quite high. Especially when the
motor is a crappy one. Lots of import motors are crummy motors. They
sometimes use less wire in the start windings which leads to lower
resistance and higher current draw. Soft start controllers are
available but can be expensive. Is the motor a capacitor start motor?
Maybe the cap is not up to snuff. Still, I'm surprised that if the
motor is wired to a 100 amp supply the voltage would sag that much if
nothing else is using the same leg of the incoming supply the same
time. What other loads are connected to the leg supplying the swamp
cooler motor?
Eric


I live in Swamp Cooler Country. Far too many of the low end
portables come with utterly crappy motors and Ive seen this many
times. It may be better to simply replace the motor with a decent US
made motor, with proper run/start caps


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Default Lights dim with swamp cooler.

On Wed, 12 Jul 2017 12:57:50 -0500, Pete Keillor
wrote:

I recently had to replace the entire breaker panel at the beach condo.
The original aluminum bus bars were corroded, and burned on some high
amp breakers. We had several appliance board failures before we
figured it out. It was also exacerbated by voltage swings due to the
utility replacing all the feeders down the island.

The original breaker panel had paint and texture sprayed on the
interior, and had probably been soaked in salt water during Ike
because the original builder not only went cheap on the panels, but
some of the patio soffits were sheetrock instead of hardie board,
causing disintegration and much wind blown water damage to all units.
The new ones are copper.

Pete Keillor


Silver sometimes burns out too...

https://photos.app.goo.gl/QR9ktCUdYvqeB5NA3

https://photos.app.goo.gl/fnUHe832D1qVWw202




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