MTH Engine Suddenly Gets Hot & Blows PS Fuse

If it jammed and wasn't moving the motor may have overheated and damaged the insulation.  I would inspect the motor/s.  Is this steam or diesel?  G

I think your transformer is a bit to small for your train and lighted passenger cars. Your transformer is a 50 watt. I had similar problems when I started in O gauge and used a 40 watt transformer with my steam engine and 4 passenger cars. It would run for a little while and trip the thermal breaker. If I put the smoke unit on it would trip it immediately.  I then went to a 75 watt (Z750) with no problems

 

 

You might also check for a traction tire that came off and jammed in the wheels.

Barry's on to something, I had a diesel throw a tire and jam up the works at the club layout, it cooked the 5V PS/2 board before I noticed it was going very slow and laboring.  That's what happens when you don't pay attention to what's going on.

Thanks guys. Checked & the traction band is where it should be. So this morning I turned on the track/train & it's been running fine. Last night when the PW breaker kept tripping I was trying to run the engine right after I found it had gotten stuck & like I said there was a distinct smell & under side of the engine was hot to the touch. Perhaps I needed to let the engine motor cool off before trying again and all is OK? How can I check to see if there's other damage?

Ok something still not right. Engine ran fine in forward but when I go into reverse it struggled a bit & PS breaker blew and I could once again smell that distinct smell under the engine. I guess I'll have to open her up to see if I see anything in there.

 

One other question... Right now I have 5 cars being pulled by this engine. Only 3 are light but the other 2 are at a bit heavier than the passenger cars. As the passenger cars number grows does that increase the wattage being passed through the PW much?

Power the engine and watch the drive rods to see if they bind. The rods will bend from picking-up the engine with your hands on drive wheels. I have had this experience.

 Checked & the traction band is where it should be

Not to be a PITA, however, there are two traction tires.

Ok both good sugestions. I took a close look at all the wheels & drive rods & all looked good. I opened up the engine to inspect and nothing obvious like "burn" spots, binding. But spinning the motor by hand had some whining noise and that burning smell is coming from the motor section. PS3 board looked fine & did not smell so after cleaning her up good & putting her back together I ran her again and runs fine for a while but after about 4 minutes she stalled on a turn and I could see the lockons flicker & then PS fuse kicked in. I removed all passenger cars to test again and this time the engine would not move more than a few inches before PS fuse blew. Also when I picked up the engine off the track it's hot to the touch underneath. Not scolding hot but certainly hotter than what I would expect normal to be so my guess is the motor, gears, or PS3 card but something's going on with the engine that seems to be creating a power surge that trips the fuse on the PS. Guess I'll have to call MTH and send it in for service.

If you overloaded the motor, it could have been cooked.  The motor shouldn't make any "whining noise" when you spin it!

Maybe that's the problem. It's not really whinning but I do hear something like that when I spin it by hand. So if the motor is cooked would it still run for a while before it overheats and trips the fuse?

A useful test is to unplug the motor connector and run the motor on a DC bench supply and see if it draws excessive current.  It should not draw more than a few hundred milliamps with the wheels off the track and just running free.

 

If you look into the ports of the motor do the copper windings look bright, or are they dark.  Dark is a sign of an overheated or damaged armature.  G

One of my Hudson's over heated, I noticed hesitating and the sound was distorted.  It became extremely hot to the touch (big ouch).  This was caused by a binded roller on the engine.  Once the roller was repaired the engine ran fine again (Big thanks to Marty).

I'm just going to have to take it in to an MTH authorized service center nearby. I don't feel comfortable hooking up the motor to a power supply in the event I screw it up worse.

 

Cooper windings looked OK.

 

Pickup rollers are not binding. They roll smoothly but good idea.

 

I wish I had another dcs engine to test with to see if the same thing happens but I don't!