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Air handler blower assembly(C) Daniel FriedmanElectric Motor Repair Q&A #4
Fix or Select Electric Motors - Q&A Set #4

  • POST a QUESTION or COMMENT about how to troubleshoot electric motors such as air conditioning compressor motors, heating equipment burner or fan motors, swimming pool motors, water well pump motors

Electric motor diagnostic FAQs set #4:

This article series describes A/C electrical motor troubleshooting: here we provide an electric motor diagnostic table, a troubleshooting guide that helps diagnose and repair most electric motor problems for motors found on HVAC equipment in buildings such as air conditioners, furnace or air handler blower fans, oil burner motors, well pumps, and condensate return pumps.

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Electric Motor Selection, Installation, Repair Q&A-4

Used pool pump motors can be re-purposed for woodworking equipment, maybe (C) InspectApedia.com IanThese questions & answers were posted originally at ELECTRIC MOTOR DIAGNOSTIC GUIDE - home.

On 2019-05-23 by (mod) - small motor stops running after 10 minuntes

Ron,

if we assume the motor isn't overloaded then it sounds as if the motor is overheating, perhaps from a bad bearing. Check first, though, for low voltage.

On 2019-05-23 19:54:34.998024 by Ron

Small AC capacitor start motor. 1/2 hp. It runs fine for ten minutes, then stops running. Then buzzing trying to start again, but it cant. The start capacitor was burned out when I got it, but I replaced it.

On 2019-05-23 19:18:07.445992 by (mod) -

Sure Art.

Commercial A/C and refrigeration compressors can actually be disassembled and examined.

Residential A/C compressors or heat pump compressors are typically hermetically sealed in a "can" and can not be disassembled for direct inspection.

However any qualified HVACR service technician knows how to make a range of measurements that can tell the condition of a motor such as measuring current draw (Amps) and if the motor runs, noting its output pressure.

However for a residential A/C compressor motor that is seized or burned out, in my OPINION it's doubtful, that it would be cost-reasonable to pay someone to cut apart or otherwise try to disassemble a residential compressor unit.

You might get your own clues about probable causes of your compressor failure by noting its service history details as well as recording any observations such as odd noises before the unit was found dead.

See details at

BURNED-OUT COMPRESSOR https://inspectapedia.com/aircond/AC_Compressor_Burned_Out.php

HARD STARTING COMPRESSOR MOTORS https://inspectapedia.com/aircond/HVAC_Compressor_Hard_Start.php

NOISES, HVAC SYSTEM DIAGNOSIS - home https://inspectapedia.com/noise_diagnosis/HVAC_Noise_Diagnosis.php - the sounds a compressor motor was making before it flipped over dead may tell us what was going on

SHORT CYCLING AC COMPRESSOR https://inspectapedia.com/aircond/Air_Conditioner_Short_Cycling.php

TIGHT or SEIZED AC COMPRESSORS https://inspectapedia.com/aircond/Seized_AC_Compressor_Motor.php

On 2019-05-23 17:12:52.011852 by Art

Is there a service or type of company that I could take an AC compressor to for testing to see if it was wired incorrectly and burned out the unit

On 2019-05-23 14:39:31.532829 by (mod) -

How odd - almost as if there is

- a loose electrical connection
- an overheating component (maybe something the fan is driving is binding, such as a pulley bearing or belt)
- low voltage

CHeck the fan motor: is it overheating?

On 2019-05-23 13:22:10.521322 by Michael

Seeking some advice here. I have an attic fan that did not work so I installed a new 1/3 HP Electric motor and Capacitor. The fan kicks on and runs for 2 minutes and then slows almost to a stop (louvers barely stay open). Any advice?

On 2019-05-23 01:20:42.650791 by (mod) -

Sounds like there is a dead short, perhaps in wiring to the motor, in a relay, or in a winding itself.

Sometimes there is a winding that doesn't open up until the rotor begins to spin, THat can be hard to detect.

On 2019-05-22 21:15:57.103499 by Jerry

4KV motor blows fuses when attempting to start. Rotor never moves but can be spun by hand. Bridge and megger tests are great. Contactor checks out ok also.

On 2019-05-12 20:39:39.318183 by (mod) -

Danny

Please see your question and a more-detailed reply now found at

ELECTRIC MOTOR is WEAK - 11 checkpoints

inspectapedia.com/electric/Electric_Motor_Diagnosis.php#WeakMotor

and let me know what you find.


On 2019-05-11 11:07:34.324219 by Danny

Gday, I’ve got a single phase motor on a lathe that won’t run the lathe. It starts and runs well without the belts on but as soon as you connect it it only just turns over. All the gearing on the lathe is fine. It’s almost like the motor is not getting enough power to run it. I’ve just replaced the run capacitor with the same capacitor as it wouldn’t start or run at all before. Any ideas please?

On 2019-04-28 14:43:50.470023 by (mod) -

Leonard, it would perhaps permit more useful comment if you can post some sharp photos of your motor and its data tag or nameplate (one photo per comment);

Generally these motors have through-screws that mount at one (or both) ends of the motor body; but a power cord is often attached through a separate removable plate at one end of the motor.

I'll have to see your specific motor to say more.

You might also want to see

GE Motor Installation And Maintenance Instructions for NEMA 140 to 500 Frame Horizontal AC Small Industrial Motors GEI – 56128H [PDF] found at
https://inspectapedia.com/electric/GE-Electric-Motor-Maintenance-Instructions.pdf

and also this GE ECM electric motor maintenance guide now re-branded as Genteq - the Genteq logo has replaced the GE ECM, GE Commercial Motors and GE Capacitors logos

GENTEQ ECM ELECTRIC MOTOR MAINTENANCE GUIDE [PDF] (2014) at ECM-Evergreen-Electric-Motor-Guide-GE-Genteq.pdf





On 2019-04-28 14:04:13.220455 by Leonard Doyle

I have a general electric 1/12 motor which runs the auto oiler on a valve grinder serial number 5ksp21461481 , question is how does it come apart all it needs is a new cord

On 2019-04-02 16:48:56.716460 by (mod) -

I'd be interested in the current draw (amps) - could be a seizing motor

On 2019-03-14 20:02:56.559036 by Robert Theriault

small ac variable speed motor on router starts runs for a few seconds and stops, indicator on top flashes red. small smell

On 2019-02-19 23:26:31.916631 by (mod) -

I'd check voltage supply, current draw, bearings, electricsl connections,

Watch out: dont try tests if you are not safety trained or you could be shocjed or killed.

On 2019-02-19 22:05:00.479261 by A-1 Cycle

electric motor starts up but has no horse power. can stop motor by hand

On 2019-01-30 18:24:05.373140 by (mod) -

Some humming noises may be normal, Tony while others can indicate a motor that is having trouble starting or that has a failing bearing.

Please see ELECTRIC MOTOR NOISE DIAGNOSIS https://inspectapedia.com/electric/Electric_Motor_Noise.php

On 2019-01-19 02:05:47.674798 by Tony

All my electric is fine but my motor hums when cut on.

On 2019-01-19 by (mod) - my electric motor seems ok but it hums

Tony

Some humming noises may be normal, Tony while others can indicate a motor that is having trouble starting or that has a failing bearing.

Please see ELECTRIC MOTOR NOISE DIAGNOSIS

On 2019-01-19 by Tony

All my electric is fine but my motor hums when cut on.

On 2018-12-24 by (mod) - When I hardwire the motor it works.

Jeff

I'd look for a short or bad connection or connector in the system wiring or a bad fan controller.

On 2018-12-24 by Jeff

Im trying to get a fan motor working on a 2000 Tahoe. The motor quit blowing. When I hardwire the motor it works. So, I no it isn't locked up. The motor has power when it is hot wired but has no power once I plug it into the system. What could be the problem?

On 2018-10-23 by (mod) - I would like to produce 1000 volts or thousand Watts - tripping my breaker box

Sounds crazy to me. Dangerous and illegal.

On 2018-10-23 16:17:44.430477 by David Watkins

I'd like to take apart my AC induction blower motor direct drive I might add apart so I can make a permanent magnet generator motor out of it but I don't want to just produce 220

I would like to produce 1000 volts or thousand Watts vice versa by connecting a microwave Transformer to it and I have the river in my front yard so I'd like to maybe run it into my breaker box is this flipping crazy or or what

On 2018-10-11 22:08:09.421462 by (mod) -

Kava

Perhaps lack of lubrication or a failing bearing;

Other causes of motor overheating include overloading or low voltage delivery to the motor.

Good luck on your test.

On 2018-10-11 07:23:29.894130 by Kavaljeet Kaur Dhunna

What is the reason behind the motor's shaft being hot n what should be done to repair it?
[motor with 2800 rpm and 45 kilowatt]

On 2018-08-06 21:24:56.206079 by (mod) -

Partha

TURN OFF the motor and power to the system immediately to avoid killing someone.

Leave it off.

Call for help from an experienced electgrician who will trace the circuit. Most-likley there is a wiring damage or control damage that' shorting to ground, perhaps combined with improper shock and over-current protection.

On 2018-08-06 18:56:31.607076 by Partha Sarathi Bhowmick

A single Phase Motor[Coupled with a Water Pump [1/2HP] while running its body getting short. Even any person getting shock while touching the water discharge. What are probable reasons for that ?

On 2018-07-22 17:20:09.989821 by (mod) -

DK

The apology that one cannot diagnose an electric motor I briefed a text, it may be that your motor has a failing bearing or other internal component that is causing it to bind and perhaps overheat. Ask an electrician to check the voltage being delivered to the motor.

On 2018-07-22 12:30:53.021679 by D k singh

Motor is not taking load + noisy+heat and smell


On 2018-06-20 11:46:21.074661 by (mod) -

In the article above see the diagnostics in

Table B: 7 Things to Check if an Electric Motor Starts but Overheats and Trips its Reset Button or Runs at Abnormal Voltage or Current Levels

On 2018-06-20 09:05:25.226506 by Well water pump

Moter over heating

On 2018-06-19 15:55:06.235263 by (mod) -

Martin some guesses include

a bad motor bearing

low supply voltage

an internal short in the windings

excessive or abnormal loads on the motor

Leave the motor OFF until it's repaired or replaced.

On 2018-06-19 14:07:34.875808 by Martin

220 motor spins but draws huge amps and trips breaker what could be problem

On 2018-05-26 15:20:20.390123 by (mod) -

I'd start by checking the voltage being delivered and the current draw during use.

I'd look for overheating - that can damage a motor and cause power loss.

I'd look for wood dust clogging the vent ports and then contaminating the motor windings.

I'd check the motor lubrication requirements & lube history.

I'd check the motor's ability to spin with power disconnected - are the bearings bad?

On 2018-05-26 12:06:06.409011 by Foy

I have a Delta BOSS spindle sander with a 1/4 HP 1 PH 1725RPM induction type motor. While the motor starts and spins up it has no power when you start to sand a piece of wood. The motor slows to a stop. Remove the wood and the motor spins back up. What do you think is causing this?


...

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