2 Speed Motor Continues To Run On Slow Speed - Electrical - DIY Chatroom Home Improvement Forum

Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > Electrical


Thread Tools Display Modes
Old 11-12-2011, 04:30 PM   #1
Join Date: Nov 2011
Posts: 2
Rewards Points: 10

2 speed motor continues to run on slow speed

I am new to this forum. I was hoping you folks might be able to help me with an electrical problem Im having with my Intertherm electric furnace that has a 2 speed motor. One day I noticed that the furnace was running on a slow speed and wasnt heating. The thermostat wasn't calling for heat. After a lot of fussing around and doing internet searches for answers I thought I had the answer. I thought it was the sequencer so I oredered a new sequencer and received and installed it today. The furnace still does the same thing. I started looking closer and I find that the wire to the motor for the low speed isnt even hooked up. If I am reading things right the Black wire powers the high speed and the Red wire powers the low speed, and the red wire isnt hooked up and never was. But somehow the motor continues to run at slow speed after the furnace shuts down. It runs on high speed and heats just fine when the thermostat is calling for heat. It seems to me it must be a problem in the motor itself. Has anyone out there ever seen this before? Thanks for any help you can give. Rob


Rob Fayette is offline   Reply With Quote
Old 11-12-2011, 08:03 PM   #2
Join Date: Nov 2007
Location: Nashua, NH, USA
Posts: 7,971
Rewards Points: 1,548

Seems to me as if there is a ground fault in the motor, one cause is the enamel insulation on coil wiring somehow deteriorated and the wire coming into contact with grounded metal parts.

Is the motor 120 volts or 240 volts? A 240 volt motor with a ground fault could well be energized all of the time, including when it should be "switched off" and the switch controls just one of the two power leads.


The good conscientious technician or serviceperson will carry extra oils and lubricants in case the new pump did not come with oil or the oil was accidentally spilled, so the service call can be completed without an extra visit.

Last edited by AllanJ; 11-12-2011 at 08:05 PM.
AllanJ is offline   Reply With Quote
Old 11-13-2011, 05:34 PM   #3
Join Date: Nov 2011
Posts: 2
Rewards Points: 10

Hi again,
I found out what was happening to cause the blower motor to run at slow speed. I found that one of the heating coils what shorting out to the frame that it is mounted on. This was causing this coil to stay partially heated up and also it was allowing a partial voltage to be applied to the high speed feed to the motor. Part of the heating coil that shorted had become distorted enough to touch the frame its mounted on. All I did was bend the coil a little where it was distorted. I could feel it stick a little to the frame when I bent it like it was welded there a little. I put it all back together and now the furnace works fine.
Rob Fayette is offline   Reply With Quote

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
Broan variable speed motor m0t0rgeo Electrical 1 09-22-2011 01:58 PM
Variable Speed Vs " Multi - Speed " alecmcmahon HVAC 15 04-14-2011 03:06 PM
how to build a single phase induction motor sashman Electrical 3 03-31-2011 07:18 AM
changing speed of grinder MeanGene Electrical 2 03-19-2011 09:53 AM
Chain saw Barry J Landscaping & Lawn Care 7 01-28-2009 01:11 AM

Top of Page | View New Posts


Search Engine Friendly URLs by vBSEO 3.6.1