Electric motor capacitor diagnosis, repair & wiring questions and answers.

Choosing, installing, & troubleshooting starting capacitors & run capacitors used on electric motors.

This electric motor capacitor article series explains the selection, installation, testing, & use of electric motor starter start and run capacitors used on various electric motors found in or at buildings such as air conditioner compressors, fan motors, some well pumps and some heating equipment.

Page top photo of air conditioner compressor/condenser unit capacitors taped into the unit was provided courtesy of reader C. Dale and is discussed on this page.

More Electric Motor Starting Capacitor or Run Capacitor FAQs #3

These electric motor start or run capacitor questions & answers were posted originally at CAPACITOR TYPES, for MOTORS - be sure to review that article.

Also see CAPACITOR SIZE DETERMINATION for ELECTRIC MOTORS.

Or see ELECTRIC MOTOR DIAGNOSTIC GUIDE

On 2018-10-08 by Ben

I have a 1hp capacitor start motor that will not run (no buzz or anything). It is getting power to the motor. With power on, the wire to the start capacitor giggled (I think it touched the motor housing) the motor sparked and started running. What is the problem and how do I make it run?

On 2018-09-29 by (mod) - do I need a capacitor?

I suppose there could be a bad run capacitor. It's also the case however the a motor that cuts out when it gets up to full speed is cutting out because of winding Or wire is opening up at that higher speed. If that's the case the motor will need to be repaired or replaced.

On 2018-09-29 by Carol smith

I have a 42 inch industrial drum fan with a 1/2 hp motor. It will start fine in either low speed or high speed but then cuts out. The plug in cord is grounded but the slot on the motor has no ground wire. Is this my problem or do i need a capacitor?

On 2018-09-08 by (mod) - centrifugal switch in motor

Dixon

An electric motors that switch out the starting capacitor from the circuit there is typically a centrifugal switch that is built into the motor such that is a motor gets up to operating speed switch opens. I don't think you can very easily added that future

On 2018-09-08 by Dixon

How to install a breaker to a starting capacitor in a.c motor so that when the motor starting I put off the breaker?

On 2018-07-09 by (mod) - a problem in the motor beyond the capacitor itself

Sounds like it could be a problem in the motor beyond the capacitor itself. In any case there's a second problem. If you have a double pole breaker and only one side is tripping the breaker is not working the way it should.

On 2018-07-08 by Dan Paris

Hello. My pool motor only humms then trips one side of the breaker after 15-20 seconds. I'm thinking it may be the capacitor.

The pump is only a couple years old. Is the capacitor a simple fix I can do myself. As long as I trip the circuit breakers do I need to be concerned about a shock from the capacitor itself and can I just connect each side of it to ground to discharge the capacitor if that is a concern?

I just remember how you were always told to be very careful of the capacitor in old televisions so trying to make sure I'm not gonna light myself up! Thank You.

On 2018-07-21 by (mod) -

Perhaps a bad starting capacitor.

On 2018-07-21 by Frederick Malyon

Motor does not start to spin unless I turn the motor what Ii scause ?

On 2018-06-30 by (mod) - Craftsman air compressor model 919.165140 won't run

Pete some simple tables and suggestions are at

CAPACITOR SIZE DETERMINATION for ELECTRIC MOTORS https://inspectapedia.com/electric/Motor_Capacitor_Selection.php

where I include some AO Smith motor references and contact information, some tables of basic capacitor values vs motor size, voltage, current, horsepower

There are calculations, even a website offering them, of capacitor values but in my opinion one would be smarter to check with the manufacturer or take the motor to a rebuild shop.

On 2018-06-30 by Pete

I have a Craftsman air compressor model 919.165140.

I need to replace the run capacitor but the label is
obliterated. Can you provide the start run for the A.O. Smith MO-9083.

If not can you provide a formula to calculate the run capacitor value? It is very difficult to find actual capacitances for for motors.

On 2018-02-01 by (mod) - Could be having trouble starting against a head pressure.

Could be having trouble starting against a head pressure.

On 2018-01-28 by Air compressor issue

Have a 5HP 22gal air compressor. Charged to full capacity then when it needed to recycle motor sounded weak, fan made a couple of slow complete rotations, then stopped. This happened 3-4 times before I unplugged. when I plugged back in the same thing occured.??

On 2018-01-20 by Jo Gusto

Just in case it was not clear, I seem to believe the centrifugal switch is working normally. The springs work, there is freedom of movement, and I hear it click over when I bench test the motor.

I also have confirmed the spa piping to be free and clear and no air lock present AFAIK (Several drain and refill cycles have not changed the symptom in any way; if it were air lock, I’d think it would have resolved at least one of those times.)

On 2018-01-20 by Jo Gusto

Hi, love the knowledge on this site. I have a Centurion A.O. Smith spa jet pump.

When in the spa and properly primed, the pump starts well, spins up to running speed, then almost immediately stops running, spins down, but then surges and spins up again. This repeats on an approx 3 second cycle. On the bench with no load, it spins up to speed and runs continuously. I checked both start and run caps with a Fluke DVM; mfd values spot on, no shorts, caps look perfect.

I visually checked the centrifugal switch and it looks to be ok. At this point, I have to think that the run winding might be open and that’s why it oscillates under load but runs smoothly without load.

Yes the Klixon phenolic motor protector seems ok, there is just fractional ohms between the terminals. Any ideas? Thanks in advance.

On 2017-11-29 by (mod) -

David

That sounds to me like a bad start/run capacitor

On 2017-11-28 by David Paul

The water motor does not start at once...wire gets heated when it not starting...once it started it works fine...any solution? ? ??

On 2017-11-26 by (mod) - Sounds like a bad relay or control board

Craig

Sounds like a bad relay or control board

On 2017-11-11 by Craig Earnshaw

My evaporative ac starts but will run at one constant speed. All othe functions of the pne comfort controller are working. The controller sends the signal to change speed but nothing happens.

On 2017-10-17 by (mod) -

Generally, Brian, if you're within the same uF range, proper voltage, etc. you will be ok with the next larger cap.

On 2017-10-17 by Brian

The capacitor on my blower motor is shot. I cannot find an exact replacement. Can i use a lower or higher rated capacitor or does it have to be the exact one?

The one that is shot: CBB60 SH DB, 65uF +/- 5% 50/60 Hz, 300Vac Cl. B, 25/85/21

All the ones i find that are close to that are either higher voltage or lower uF rating. What are my options with this issue?

On 2017-10-06 by James

I was using my bench top drill press, 1/3hp motor. After about ten minutes of use the motor suddenly slowed and seems to be drawing more currant than normal.

I disconnected belt, (isolated to just motor), turned on and it runs slowly and when I turn it off, I notice the light on the same outlet gets brighter which leads me thinking motor is drawing to much amperage.

Motor otherwise turns freely, no bindind, no burning smell, all seems normal yet it runs slow and like I said, seems to be drawing to much currant to run. Any ideas? Thanks...

On 2017-09-29 16:02:51.704648 by (mod) -

Yes, or there could be an open or broken wire.

On 2017-09-28 by J Bean

When i turn my air compressor on, there is no noise hum etc. There is current at the start cap leads. Could my start cap be bad ?

On 2017-09-21 by Chris Lakewood HV-18 fan

I have an old Lakewood HV-18 fan. It started to move super slow at start up while humming a bit and then after a few seconds it worked fine. Before I could oil it - it stopped working all together. Now it doesn't hum and it doesn't start. It does nothing. Did I ruin the motor or is it possibly the capacitor? Or could it be something else? Thanks in advance.

On 2017-09-04 by craig

Hi, My Bonnaire Integra evaporative air con unit is RF controlled, has both a start and run capacitor.

My electrician recently changed the run capacitor and since then there is no variable speed adjustment.

My fan spins at a constant speed no matter the setting on the controller and has done so since the work was done. I have tried to get him to return but he will not respond as I live very remote. Any ideas?

On 2017-08-23 by (mod) - Replacing a suspect start capacitor is the least expensive thing to try.

Joe,

Replacing a suspect start capacitor is the least expensive thing to try.

You'll know it's not the cap but a failing motor, perhaps a bad bearing, if the cap makes no difference.
I'd also check the voltage level and the variable speed controller itself.

On 2017-08-22 by joe

I have a variable speed wood lathe that is slow starting and then it kicks off the circuit breaker.I think it is the capacitor. Is this the result of a failing capacitor?

On 2017-08-10 by Greg

My account compressor fan won't start on it's own. Replaced start capacitor same thing. It will run when manually spun.

On 2018-07-31 by (mod) - most-common explanation for an intermittent failure of a motor to start if you're sure that the start capacitor is good is a failure in the motor itself

Dale C

The most-common explanation for an intermittent failure of a motor to start if you're sure that the start capacitor is good is a failure in the motor itself. The failure an be in a motor bearing or in a winding.

So from a distant point in central Mexico (avoiding the wall), and given no more knowledge of your system, that's our best guess.

Your "over-worked" theory has some merit but not entirely.

I mean to say that in hot weather an air conditioning system can run almost constantly without expecting to fail. So I speculate that it's more-likely that the heavier use of your downstairs AC simply sped-up the discovery of failing components.

On 2018-07-31 by C Dale

Good day! So, I've been dealing with this for about 4 weeks now. I have a 3-story home (basement, main floor, 2nd floor), with 2 A/C systems (2 indoor units and 2 outdoor units, both Trane XB10s (1xTWB0030 for downstairs and 1xTWB0018 for upstairs)).

Back in May, we started getting some water leaking near one of our upstairs lights. So I turned off the upstairs A/C and the leaking stopped. I was working about 60hrs a week at the time, so I let it go and forgot about it.

Beginning of July I took a week off work, and decided to work on it. Ended up just being a broken pvc drain pipe; so I fixed that and turned the upstairs A/C back on.

I mention all this to say that the downstairs unit was cooling the entire house (2700sq ft not counting the basement) for about 6 weeks, and I'm sure this stressed the system. After a day or two I noticed that the upstairs unit wasn't cooling, just blowing air. I went outside and the compressor was running, but not the fan.

I used your website to figure out I needed to check the capacitor and connector, I did and ended up replacing the capacitor and it started right up and has been working fine for the last 4 weeks. 2 days after I did that, the downstairs A/C stopped blowing cold air, just blowing air around and the room temp was rising.

I went outside, and same effects, the compressor was on, but not the fan. I opened the unit and it was obvious the previous owners had jerry-rigged a new capacitor (40) and hard-start capacitor (7.5) into the system, evidently with a new motor at some point, as neither the fan or the capacitors matched the parts list (see image of dual capacitors)

I checked the connector and it was working, so I replaced the capacitor with the original capacitor (5/45) listed in the documents and the A/C started working, but needed a push start the first time and every so often to get going.

After 2 weeks it just stopped starting the compressor fan, so I replaced it with a capacitor (7.5/40) that matched the specifications of the previous two-capacitor setup. It started right up, no push start. However, in the two weeks since, the fan will occasionally not start. If I go out and pull the outside breaker to check on the system, and plug it back in, most of the time the fan will start back up, but sometimes even that doesn't do it.

Last night the fan wasn't running, but the compressor was (thermostat set to 69 degrees, reading at 75 degrees). I went out and pulled the outside breaker, and re-inserted it 3 times. Fan didn't start. So I turned off the system for the night. This morning, I turned the system back on (set thermostat to 68, reading at 73 degrees), and the system started right up.

In the 2 hours since the system has started cooling 2 times (to maintain the 72 degrees I set it at), and it's worked each time. Any ideas on what is causing the fan to occasionally not start? My very untrained mind thinks it's probably either the fan is going bad from being overworked for 6 weeks, or maybe the connector or circuit board is having hiccups.

While it's working at the moment, I want to get this figured out before it causes the compressor to fail. Thank you in advance, and have a great day!

On 2018-07-08 by (mod) -

See

HOW TO WIRE A START/ RUN CAPACITOR

https://inspectapedia.com/electric/Starting_Capacitor_Wiring.php

On 2018-07-07 by Anonymous

i have red wire from contactor to C and blue wire from compresor to herm and brown from motor to fan it alright?

On 2018-07-07 by (mod) -

Or the cap was wrong value or wiring or another defect is blowing the capacitor.

Test the new capacitor that you just replaced.

Watch out: if you're not trained in electrical work you can be shocked or killed.

On 2018-07-07 by anh nguyen

i replace capacitor yesterday but fan just run few hour and stop. turn off or i use stick move fan it run again so motor bad? danioefriedman

On 2018-07-06 by (mod) -

Anh

If replacing the start/run capacitor didn't get the fan going,
With power OFF and disconnected - so you don't kill yourself -

1. see if the fan is hard to spin - if so it's bearings are shot

2. see if the fan drive shaft has play in any direction - also could be bad bearings

3. if those fan problems are not present you might take the fan motor out of the unit and have it tested by an electric motor repair shop - some problems only show up when the electric motor is actually spinning

On 2018-07-06 by anh nguyen

My condense fan out door hard to run. i need fan by my self. and run a few hour stop again and not start. i . replace capacitor already..

On 2018-06-06 by (mod) -

Probably the compressor is overheating. If the fan runs and air flow isn't obstructed, the motor could be failing. Your service tech might check current draw.

On 2018-06-02 by ardee

My Rheem compressor unit suddenly stopped running after it had been running a while during a 90-degree high humidity day. The compressor is pretty old (at least 10 years or more). Both capacitors and the fan motor were replaced about 2-3 years ago. A trick someone told me about that I have used before is to spray water on the radiator fins to cool them. After about 2 minutes, I cut off the water. The unit came on and stayed on through the night. The same thing happened the next day. What is the suspected bad part?

On 2018-04-13 by (mod) -

David

Watch out: opening control boxes, touching electrical connections you can be shocked or killed - especially when working around plumbing and possibly wet conditions.

Your plumber or electrician would use a voltage tester or even a voltage stick that will buzz without having to actually touch wires or connectors to see if voltage is being delivered to the pump control switch and to other control points if there's a separate relay box.

Yes a blown capacitor would keep a pump motor from starting if that's what you're seeing, but it could be something else, such as a device to reduce damage from lightning strikes.

You can use the picture frame icon to attach photos if you like.

On 2018-04-13 by David

The power to my water pump is gone.
I thought that a fuse had blown but that does appear to be the problem. The power light is off.There is a white cylinder in the control box which I think is called a capacitor. If this is damaged will the power light be off
Need an answer a.s.a.p.
Thanks

On 2017-07-27 by Rahul

Dear Sir/Madam,
Recently I Installed 1HP submersible pump in my home bore well. Its working very fine when I install it in 50Feet depth. if I increase 1 more UPVC pipe(10feet pipe length - that is 60 feet) then the motor only "hums" even its doesn't start. I used 3 colour submersible 1100V Texmo wires(300 feet length) for bore well and RAJ Capacitors(150 for starting and two 36 for running(running capacitors are connected parallely).

The voltage range comes to home is between 190V to 230V(will be vary from day and night). The dealer said this motor will support upto 250 feet of head length but now it worked only for 50Feet. In 50 feet motor runs well and meter shows 8A for running and 15A when I press start button. In 20feet itself I had water in bore well. Its a strange problem for me. Kindly give me a solution.
Regards,
Rahul

On 2017-07-06 by (mod) -

Mike,

Be sure that the run capacitor is within 5% of the cap specified on the motor data tag.

On 2017-07-06 by mike

i have an HRP 1515s model n i need t service it so i bought a motor start capacitor n a run capacitor bt am nat sure if i they mech, lyk is de ratio fr both de capacitors t run de motor owk...when i have 140/5% microferal with 250 v run capacitor nd an 30-60 uf +5% and 440 v motorstart capacitor both conected to the motor will the motor run at all and if yes for how long will dat last

On 2017-06-16 by Ben z

Replaced 60/5 capacitor with 60/7.5, had to move thermostat to get it to start. Ran fine for 30 minutes. Then then fan stopped turning. No noise.

On 2017-03-28 by (mod) - Adding refrigerant is never a repair for an A/C or heat pump that simply doesn't start.

Checking

Adding refrigerant is never a repair for an A/C or heat pump that simply doesn't start. The problem is more likely to be

- a control or relay - no power is delivered to the compressor motor

- a bad start/run capacitor - motor hums but doesn't run

- a seized compressor motor (check current draw) - motor may hum or may trip breaker

- on occasion a compressor has trouble starting against high head pressure either from being cycled on-off too quickly or from a bad TEV.

See inspectapedia.com/aircond/Air_Conditioner_Wont_Start.php AIR CONDITIONER WON'T START
and
inspectapedia.com/electric/Electric_Motor_Diagnosis.php ELECTRIC MOTOR DIAGNOSTIC GUIDE
also this article should be helpful
inspectapedia.com/aircond/HVAC_Condenser_Unit_Diagnosis.php COMPRESSOR / CONDENSER DIAGNOSTICS

I'd welcome further comments & questions.

On 2017-03-28 09:45:23.265981 by Checking compressor SCR windings

I have a trane 2 stage heat pump, 9 yrs old, freon capacity 19 lbs r22, initially compressor not running then checked freon level with gages. Equalized at 90 lbs. Thinking might be a little low on freon, started adding and compressor kicked on. As I'm adding a couple lbs later Guage didn't budge either side. Go inside to switch tstat to hp and nothing on compressor. Heard switching valve activate but no compressor on hp or ac now. Now I'm thinking bad compressor or txv. Usually if txv bad either high or low press will rise immediately depending on state of locked up txv or blocked. Anyway I check what I know I can see, voltage out to compressor 240v, suction or discharge not rising when adding and compressor feels hot on top side. Removed wires from compressor on 2nd stage contacts and ohmed out windings finding overload or open on common winding. Ok, what doesn't make sense the compressor did run shortly with no rise in pressures. Am I missing something or can I get a possible maybe from you saying I'm on the right track with compressor being bad? Any help would be appreciated. Thanks,
Dan

On 2017-02-26 18:55:09.757567 by (mod) -

Possibly, or the pump may be damaged if it was run dry.

On 2017-02-26 by Anonymous

My well pump normally runs just fine. Yesterday I noticed the water pressure in the house was weak. Then there was no water at all. I went out to the well house and the motor was running. Went back inside and had water again. Today I went out and turned on the water at the well house to make the pump come on.

It came on but made a sound like it was struggling to come on at first and then it got up to speed. So once it gets running it runs fine but it doesn't always start up when the pressure switch callas for it to turn on. Does this sound like the start capacitor has gone bad?

On 2016-12-02 by (mod) -

Humming at the outdoor compressor/condenser unit could be a bad compressor motor but also from a bad relay or a bad fan motor or simply a bad fan start/run capacitor.

Search InspectApedia.com for HUMMING COMPRESSOR UNIT and also

search for HARD START CAPACITOR to read details.

On 2016-12-02 by Rickylee

Realized my condenser fan wasn't turning so I manually started the fan.it came on but at a slower speed , l could hear a hum cycle every so often. Thought for sure it was the condenser motor, bought a new one, no change out 328.00. While the panel was off , the humming was coming from the compressor, any thoughts.

On 2016-09-10 by (mod) -

Jon

For a detailed reply to your question please see BASIC ELECTRICAL TESTS for BURNED OUT COMPRESSOR MOTORS at https://inspectapedia.com/aircond/AC_Compressor_Burned_Out.php#Basic

Watch out: if you are not trained and equipped for safe electrical testing you could be shocked or killed

On 2016-09-10 by johnteh

I had the summer A/C inspection done was told the compressor capacitor was indicating a short life because the compressor mega ohms was 200 which is very low for a unit that is only 2 years old. recommendation was to replace compressor capacitor with a hard start to prolong compressor life. Are compressor capacitors difficult to replace/install? They don't seem to be, since they have only 2 wires.

On 2017-07-27 by Rahul

Dear Sir/Madam,
Recently I Installed 1HP submersible pump in my home bore well. Its working very fine when I install it in 50Feet depth. if I increase 1 more UPVC pipe(10feet pipe length - that is 60 feet) then the motor only "hums" even its doesn't start. I used 3 colour submersible 1100V Texmo wires(300 feet length) for bore well and RAJ Capacitors(150 for starting and two 36 for running(running capacitors are connected parallely).

The voltage range comes to home is between 190V to 230V(will be vary from day and night). The dealer said this motor will support upto 250 feet of head length but now it worked only for 50Feet. In 50 feet motor runs well and meter shows 8A for running and 15A when I press start button. In 20feet itself I had water in bore well. Its a strange problem for me. Kindly give me a solution.
Regards,
Rahul

On 2017-07-07 by ndlovvini@gmail.com

Hi

I wanted to construct a charging system using a car alternator and a motor. What i need to know is that is it possible to run the motor without start and run capacitors. The motor is 370 watts @ 1.84amps.

Thank you.

On 2017-07-07 by djvski126

I have a two speed spa motor that runs fine on high speed but starts and stops repeatedly on low speed. Motor has two capacitors. Any ideas why it wont stay running on low speed?

On 2017-06-28 by Lorraine

The motor on my well does not start. If start capacitor is bad will motor at least hum? (It doesn't hum or make any sound. ) could capacitor be bad with a silent motor? If capacitor is good what do i look at next? I assume the motor is my problem.

On 2017-05-10 by (mod) -

With the warning to be careful of the risk of fatal electric shock comma I would expect that you would replace the questionable start or run capacitor.

On 2017-05-10 by Innocent

Enter your comment here
my capacitor start capacitor run motor runs slowly and then trips power. when i take out one of the capacitors then then motor runs smoothly. what could be the problem and what do you recomend i must do.

On 2017-04-29 by (mod) -

Bri

I am not as smart as your repair electrician, but I'd be surprised if a small change in the starting capacitor of 5 uf would explain the pump failing with burned-up wires.

More likely the pump is overloaded, running dry, receiving low voltage, or has a bad bearing. Take a look at other causes and repairs at ELECTRIC MOTOR DIAGNOSTIC GUIDE

On 2017-04-29 by brillante cinco

For about 4 or 5 years, my 1hp electric water pump bronze wiring inside the machine burnt. my electrician is still fixing it today but recommended me to buy a capacitor with lower from my 25UF to 20UF. however i see it in my old unit (capacitor) which is still functioning labeled at +/- 5. do i need to buy new one?

On 2017-02-26 by (mod) -

Thomad
I can't tell from your note if the problem is the motor or its start / run capacitor. If the motor hums but doesn't run I'd try replacing the capacitor.

On 2017-02-26 by thomad

on my ac.when i turn it on.the blad wont turn.when i push it.it spends for 2seconds

On 2017-01-05 by Kirk

Dan - Thanks!

On 2017-01-04 by (mod) - saw won't run

Kirk

I am guessing that the heavier dado type saw blade (mine is quite heavy) the added torque is loading the motor - just as you suspect. A bad starting cap is a place to start, but the run cap could also be defective, OR the motor itself is failing, perhaps with a binding bearing.

I'd expect you to see the saw bog down when ripping a heavy board even with the regular blade if you push wood too fast. That'd also be diagnostic.

You can ID the motor and its model and serial number from its data tag, then consult the manufacturer about their recommended capacitors if you don't see that data on the motor's tag.

On 2017-01-04 by Kirk

I have a radial arm saw that runs fine with a single blade. When I setup a dado blade, starts for a few seconds and quits. After 5-6 seconds it tries to start again. This repeats until I turn the switch off. I was thinking that the startup capacitor didn't have enough strength to get the motor running with the heavier dado blade so I replaced it with one that was the same rating. No fix.

What could be wrong? Is it possible that someone replaced the startup cap with one that is too small? I am guessing that the motor is 2.5 - 2.75 HP. The Capacitor is rated at 161-193 micro farads. Is the cap too small? Again, it starts and runs fine with a single blade.

On 2017-01-03 by (mod) - buzzingnoises from Nibe heat pump

Tobie
It's important to track the buzzing noise to its source as the implications vary. A loose screw or fitting: tighten it, perhaps with some lock-tite. A buzzing control board relay: will need replacement soon. Buzzing from shorting wiring: risk of fire. Humming from a hard-starting compressor - start saving for a costly repair.

On 2017-01-03 by Tobie

I have a Nibe F205p Air source heat pump. The compressor has recently started making a loud buzzing sound when it tries to run, doesn't seem to do anything, before cutting off and attempting to run again minutes later repeatedly until isolated. Noticed that the capacitor is sizzling slightly at the same time it attempts to run, but no signs of it blown/leaking.

Does this sound like a capacitor issue or compressor on its way out? Cheers

On 2016-11-18 by Charles Smith

I have a Sony TC-377 reel to reel with a 1.5uf run capacitor. When I first got it, the motor wouldn't start at all unless I rotated it by hand. It had lots of torque once hand-started, and would FF and RW the tape quickly. I replaced the capacitor with a ceiling fan run cap (1.5uf 250V) and it started reliably now, but the torque was significantly less. I figured at least it's starting and stopping...

but it only lasted for a couple weeks of intermittent use. Now it's back to not starting reliably. On a cold start up (hasn't been energized in a few hours), if I turn it on and wait about 10-15 seconds, the motor will start to turn ever so slowly, and then it will catch. Or I can start it by hand and it will start immediately. In either case, once it's started it will start and stop and restart reliably until I turn it off and wait a few hours. Then it exhibits the same problem all over again.

Did I get a bad run capacitor? Or is there some other problem? Thanks!

Charles.

On 2016-07-15 by (mod) -

Replace the start/run capacitor and let me know if that fixes the trouble.

On 2016-07-13 by David

Top fan starts but runs slow till you give it a push this is an a/c unit?

...

Continue reading  at MOTOR CAPACITOR TYPES or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see these

Recommended Articles

• BASIC ELECTRICAL TESTS for BURNED OUT COMPRESSOR MOTORS
• CAPACITOR TYPES, for MOTORS
  • CAPACITORS for HARD STARTING MOTORS
  • CAUSES of HARD STARTING ELECTRIC MOTORS
  • CAPACITOR SIZE DETERMINATION for ELECTRIC MOTORS
  • COPELAND ELECTRICAL HANDBOOK [PDF]
  • HARD STARTING COMPRESSOR MOTORS
  • HOW a STARTING CAPACITOR WORKS
  • HOW to TEST the MOTOR to ID TERMINALS
  • LOCATE the STARTING CAPACITOR
  • MOTOR CAPACITOR WIRING GUIDE
  • STARTING CAPACITOR SAFETY
  • TEST a MOTOR START or RUN CAPACITOR
• ELECTRIC MOTOR CENTRIFUGAL SWITCH or PTC PRD
• ELECTRIC MOTOR DIAGNOSTIC GUIDE
• HARD STARTING ELECTRIC MOTOR CAUSES

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MOTOR CAPACITOR FAQs-3 at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

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INDEX to RELATED ARTICLES: ARTICLE INDEX to ELECTRICAL INSPECTION & TESTING

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