Whirlpool Gas Dryer motor overheats and shuts-off

[animateme]

Hello,

I have a Whirlpool Gas Dryer model 7MSGDS800MQ1 which has the problem of shutting off after about 15 to 20 minutes of operating.   I gather that it is the motor that overheats and the heat sensor safety switch is shutting down the power for protection.   While the motor is off, the timer continues to run and after about 15 minutes of cooling down, the motor starts up again.  

I have replaced the motor with an original brand-new part and the issue is still happening. 

Thinking that the drum might not be spinning freely, which could be causing the motor to overheat, I have also replaced the drum rollers, the idler pulley, the belt, the blower wheel, the rear drum felt seal, the drum plastic slide (bearing ring support) and the front panel felt seal.    All this made no difference.

To discard the possibility of the motor getting overheated due to an excessive heat from the gas burner, I replaced the high limit thermostat and the cycling thermostat.   Still, the issue is occurring. 

I have invested quite a bit replacing all these parts without any positive results but now its all about the challenge of fixing the darn thing!

Any ideas on what to try next will be greatly appreciated.

Thanks,

[johntech]

Have you tried running it with the duct disconnected?

Edited September 19, 2019 by johntech

[animateme]

Thanks for your reply.  I have not tried running it without the duct but this should not make a difference as the duct is only about 3 feet in length to reach the outdoors release.  I checked it and it is clear, no obstructions.

Any other ideas?

[TheHelicopterKid]

Is the timer at the same position when the motor stops each time? 

[darren412]

even though the motor shuts down after 15-20 minutes (which is common with a bad motor.)   It does not necessarily mean its the motor. you have already replaced the motor so  you may need to consider  checking  the neutral line for a bad connection at the motor wiring.  You mentioned the timer still counts down after it shuts off so i would think that you may be loosing the neutral line some where after the door switch wiring and timer switch wiring possibly making an intermittent connection and then it shuts down the motor.  Check the motor harness connection for a bad netral line going to it after the door switch and timer connection wiring to the motor harness also. 

[animateme]

Thank you for your replies.

The timer is not always at the same position when it stops.   When the motor does stop, the timer continues to run.  After about 20 minutes of the motor cooling down, if the timer has not reached zero, the motor starts on its own.   I do not believe that some bad connection could be causing this as the motor always stops after the 15-20 minutes of running and then starts on its own after 20 minutes of cooling down, which I assume confirms that the issue is the motor getting overheated and its own protection system shuts it off.   Would you agree?

Any other ideas?

Thank you,

[Quick]

Proper air flow is so important. I know you said you found no obstructions in the vent line to the wall but unless you have a lot of on hands experience you don't really know what good air flow really is. I would suggest pulling both the burner box and lint chute from the machine and inspect all you see in there and clean it out. 

1 hour ago, animateme said:

then starts on its own after 20 minutes of cooling down

That makes no sense to me unless maybe the push to start switch is shorted. I've not looked over your schematic though. 

Make sure you have proper supply voltage.

[animateme]

Thanks for your reply.   When I installed the new motor I did dismount the burner box and lint chute and cleaned them very well by hosing them down inside.

Regarding the motor starting again on its own after cooling down, I must add that the push to start switch has to be pressed after the motor has turned off.  

So, the motor turns off after about 20 minutes of running but the timer continues to run, at this point I press the start switch but the motor does not start right away, however, I do hear something "engaging" when this start switch is pressed.   After about 20 more minutes, the motor turns back on on its own, providing that the timer has not reached the zero mark.     Now, if I do not press the push start switch after the motor has turned off, the motor will not turn back on.   This start switch must be pressed at some point after the motor has stopped in order for the motor to resume running after the 20 minutes.

Does this indicate something?  Thanks,

[Quick]

46 minutes ago, animateme said:

Does this indicate something? 

To me it indicates the motor is overheating and shutting down on the overload.

But then again I can't help but wonder if you don't have a bad contact in your timer making and breaking under a load? 

[animateme]

If the issue is the motor overheating, may I ask why do you suspect that there might be a bad contact in the timer?    Would you assume that this possible bad connection in the timer might be causing the motor to overheat?

Thanks,

[Quick]

1 hour ago, animateme said:

If the issue is the motor overheating, may I ask why do you suspect that there might be a bad contact in the timer?    Would you assume that this possible bad connection in the timer might be causing the motor to overheat?

No I just see the possibility of a contact in the timer making and breaking. I've seen quite a few of those timers with the motor contact open keeping it from running. I've never seen one intermittent the way yours is behaving. But I could see the possibility.  Next time it stops try wiggling and jiggling the timer around a bit while you have your finger pushing in on the push to start switch see if it starts. Just a shot in the dark for you.

[Quick]

@animateme If you can post a pic of the model serial number tag off the dryer and the part number of the motor you installed. Where did you get the motor and how did you go about ordering it? 

What is the source voltage? Are you running it on a extension cord?

[animateme]

Thank you again for following up.   Here are the photos requested of the dryer and the motor labels.   I bought the motor from a local appliance parts supplier and it came in its original "Genuine - Factory Specifications Parts - Product of Whirlpool Corporation" box.

The source voltage is 120 V and no extension cord is being used.  Thanks,

[animateme]

Hello again, here is a slightly better picture of the dryer specs label.  I am concerned of whether this is the right motor model for this dryer.  

According to this parts supplier site, it is the right one:  https://www.appliancepartspros.com/whirlpool-dryer-drive-motor-279827-ap3094245.html

I will appreciate any feedback on this.

[animateme]

On another note, I measured the amps being drawn by the motor on the two wires that feed the power, the BLUE and WHITE wires going to the motor connector.   This was measured with the motor running only with the rear fan connected but not the belt that goes to the drum and I get a reading of around 8 amps on each.   The motor is rated to be 6.0 amps, would the 8 amps still be an acceptable measure under these conditions?     Would this still indicate that the motor is bad or not necessarily?     Thanks,

[Quick]

That's the correct motor. And I do believe it's bad. Provided you wired it correctly.

Wiring Instructions 11. Disconnect and remove the blue jumper wire that runs from the motor switch to the overload and discard. 12. Connect the blue (4M) wire from main harness to the vacant terminal on the overload protector where the jumper wire was removed from in step 11. 13. Connect the red (1M) wire lead from main harness to the 1/4" terminal marked “1” on the motor switch. IS094 (5/13) 14. Connect the red (2M) wire lead from main harness to the 1/4" terminal marked “2” on the motor switch. 15. To connect the black (6M) wire lead from main harness and the white (5M) wire lead from main harness to the motor switch, you must replace the 1/4" female terminals with the 1/8" insulated female terminals included with the replacement motor. 16. Cut the 1/4" female terminal from the black (6M) and white (5M) wire leads from main harness as close to terminals as possible with wire cutters. 17. Strip wires back approximately 1/4". 18. With barrel crimpers, crimp 1/8" insulated female terminals, included with motor, onto the wire leads. NOTE: Make sure terminals are crimped securely in place. 19. Connect the white (5M) wire lead from main harness onto the 1/8" terminal marked “5” on the motor switch. 20. Connect the black (6M) wire lead from main harness onto the 1/8" terminal marked “6” on the motor switch. 21. Reconnect ground wire. 22. All wire lead connections are complete at this point. Finish reassembling the dryer. 23. Plug in appliance or reconnect power

I don't understand all I understand about back EMF but I don't believe it should be over amping with no load. 

[animateme]

Thanks again for your latest reply.

An update on the issue, I tried running the cycle on the dryer with no hot air, only cool air, and the motor ran continuously for 90 minutes without stopping due to overheating.    With the hot air, it only runs for about 20 minutes before the thermal safety switch shuts the motor off. 

Given this, I assume that we can rule out the motor being bad or the current/voltage being the causes of the issue.  Correct?

Would there be a reason as to why the motor overheats when running the cycle with the hot air?  I checked the seal that goes between the rear motor shaft and the blower wheel to protect hot air from getting to the motor and it is good.

Any ideas?  
Thank you.

[Quick]

5 hours ago, animateme said:

Any ideas?  

I can't find a schematic on that one.

Bad motor. Please someone correct me if I'm wrong, but that motor running with no load should not be drawing 8 amps. Couple that with whatever problem it's having and the heat off that burner, down it goes.  

[Budget Appliance Repair]

Yes, 8 Amps is way to high no mater what - it should only be a maximum of 6 amps according to the rating plate.

Dryer motors generally only pull around 4-5 amps, especially with no load.