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7MSGDS800MQ1 Whirlpool Gas Dryer motor overheats and shuts-off

animateme

Premium Member
Joined
Aug 18, 2010
Messages
17
Location
Mexico
Model Number
7MSGDS800MQ1
Brand
Whirlpool
Age
More than 10 years
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,
 

Jake

Appliance Tech - Admin
Staff member
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Messages
123,974
Location
McMullen Valley, Arizona
Hi,

There is an amp rating on the motor serial number plate. Use a clamp style amp probe around the common wire (the wire going to the motor overload) and see how close it is. Remove the drum and belt and set the dryer to air fluff or no heat and you can run it to check it.

You'd need an clamp style amp meter. Like this one here: Sears: clamp style amp meter

Jake
 

animateme

Premium Member
Joined
Aug 18, 2010
Messages
17
Location
Mexico
Thank you for your reply. I do have one of those clamp type amp meters.

I am just not clear on which wire I should be measuring. Would this be at the connector (red, green, white, blue wires) or at the motor itself (blue wire)?
dryermotor.jpg
 

Jake

Appliance Tech - Admin
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At the motor itself, the dark blue wire in the photo on the right.:)

Jake
 

animateme

Premium Member
Joined
Aug 18, 2010
Messages
17
Location
Mexico
Hi Jake,
I measured the amps at the blue wire on the motor and I get 14 amps. The motor shows a rating of 6 amps. I measured with the motor dismounted and no load connected to it.
What does this mean? Should the motor be getting the 6 amps? Why would the power be higher?
Thank you,
 

animateme

Premium Member
Joined
Aug 18, 2010
Messages
17
Location
Mexico
Hi again,
I checked the amp reading again at the motor's blue wire and this time I got around 11 amps. I also measured at one of the red wires going to the connector and I got close to 6 amps.
Are you sure that the right reading is with the measure at the blue motor wire or could it be that the red wire is the right one?
Thanks,
IMG_2124_.jpg
IMG_2130_.jpg
 

bigbuck

Appliance Tech
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Mar 19, 2015
Messages
1,652
Location
From Planet Mars
Wiring diagram if needed.
 

Attachments

  • 7MSGDS800MQ1 Wiring Sheet-3979703-Rev A.pdf
    253.7 KB · Views: 115

animateme

Premium Member
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Aug 18, 2010
Messages
17
Location
Mexico
Thank you for the diagram!
I am not too familiar on how to read these but am I understanding correctly in that the wires that feed the power to the motor are the BLUE and the WHITE?
diag.JPG
 

Jake

Appliance Tech - Admin
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Yes, correct 4M and 5M.

Yes, your motor is bad, its pulling too many amps.

Thanks bigbuck!

Jake
 

animateme

Premium Member
Joined
Aug 18, 2010
Messages
17
Location
Mexico
Thank you for your response Jake. I checked the BLUE and WHITE wires going to the motor connector with the motor running and I get a reading of around 8 amps on each. This is with the motor running with the rear fan connected but no drum belt. Is this a correct measure? Does this still indicate that the motor is bad? Thanks,
dryermotoramps.jpg
 

Jake

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Yes, because its over the 6 amp rating on the motor.

The motor shows a rating of 6 amps.

Jake
 

animateme

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Messages
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Location
Mexico
I see. What could be the causes for the motor drawing more power than it should? Is it definitely the motor that is bad or could another component be causing this?

Any tests I can try to troubleshoot?

Thank you,
 

Jake

Appliance Tech - Admin
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A defective motor, contact the place where you got it and let them know, they should exchange it free of charge.

Is it definitely the motor that is bad or could another component be causing this?

Any tests I can try to troubleshoot?
Its definity defective. That's all the troubleshooting you can do.

Jake
 

animateme

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Messages
17
Location
Mexico
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.
 

Jake

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I think we already went over this and I hate repeating.:)

Your motor is bad, its pulling too many amps. Did you replace the motor?

Simple Math is the motor rating is 6 amps, its pulling 8 amps. There's nothing else it can be with or without heat. We are only taking the amp reading on the motor, not the heater too.

Jake
 

animateme

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Messages
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Location
Mexico
I have not replaced the motor.
Sorry but... again, why would the motor overheat only when hot air is being blown and not when cool air is blown? If the amps being drawn by the motor were the issue then it would also overheat when cool air is being used, right?
 

Jake

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I will ask Rick.

Jake
 

rickgburton

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Murray, Utah 84107, United States
The aluminum motor windings will oxidize when they get hot. This causes the motor to use more current. Current = heat. More current, more heat. Metal expands when heated and different metals expand at different rates. The motor shaft expands inside the bearing until it stops. The constant expanding and contracting will cause a small space between the shaft and bearing. When the motor receives 120 VAC the voltage goes from +120V to -120V 60 times a second and you will usually hear a loud hum as the motor shaft vibrates inside the motor bearing when the motor first starts. When you run it on air fluff the temperature is just below the threshold where it expands. Although the element/gas valve wires don’t go through the motor windings it does go through the motor switch. If you dried a load on air fluff it might last longer than 90 minutes but it will eventually shut off and not start. The motor is definitely bad.
 

animateme

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Aug 18, 2010
Messages
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Location
Mexico
Thank you very much for your very interesting and detailed explanation. I guess it's time to get another motor.
Greatly appreciated Jake and Rick!
 

rickgburton

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The downward spiral probably started with lint build up sucked into the motor windings. The lint build up acts like insulation and holds the heat from the motor in.
 
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