Electric Dryer Leg A drops to 0V Leg B spikes at 240V when start pushed

Status
Not open for further replies.

lummerman5k

New User
Location
Biloxi
I am in the military and came back from a month overseas and my 3 prong electric dryer would not start. I am an electronics technician (radios) so I am quite experienced with electronics and theory (although DC is my strength).


I checked all the routine no start issues, door switch, start switch and thermal resistor all have continuity when isolated. I checked voltages at the receptacle and on the distribution block of the dryer hot to hot-240V, neutral to hot A-118V, neutral to hot B-123V and nothing would happen when start was pressed. I hit start and tried to spun the drum, nothing. I ended up pulling the front panel completely off and removing the drum and checked that I have 118V on M4 of the motor switch. In order to check the motor I created a test cable from an extension cord and (cut the female end off and stripped the ends) and connected it to the dryer power distribution on the hot side that controls the motor (not the heater) and neutral then plugged it into a standard 120 wall outlet and the dryer started up like a champ so I knew the motor was good. I then plugged the original cable back in and tried to start it and it didnt work. I then opened the motor switch and the voltage all looked good. I then manually shorted the relay for heating circuit on the motor switch and and the coil heated up. I then ohmed out the timing switch and it was good.


I then opened the receptacle and put my multimeter probes on leg A and neutral, it read 118V and when I pressed the start button the it dropped to 0V and leg B was at 240V. I thought it could be a open neutral (although I dont have much experience with neutrals being a DC guy but I am familiar with electronic theory) so I connected my multimeter between the common (ground) pin on the door switch and the bare neutral wire on the service panel and it read 1.3 ohms so there is neutral connectivity throughout the circuit (I also verified that all grounds had connectivity with the neutral in the service panel).
I am now at a loss as to where to go next. I really don't have an idea of where to go next as every thing else in my apartment works as it should and I don't have the funds to hire an electrician or a repair man. Any help or suggestions would be greatly appreciated.
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
I am closing this thread, in accordance with the Forum Rules.

This site is designed for:

  • Contractors
  • Electricians
  • Engineers
  • Inspectors
  • Instructors
  • Other electrically related individuals


* This NEC Forum is for those in the electrical and related industries. Questions of a "How-To" nature by persons not involved in the electrical industry will be removed without notice.
If you feel this action to be in error, feel free to contact me via PM to explain.

A reminder to all members, if you see a questionable post, feel free to report it by clicking the
report-40b.png
button at the bottom left corner of the post.
 
Status
Not open for further replies.
Top