Author Topic: Motor does not function when setting loco motor full load current  (Read 99 times)

carpediem4570

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Motor does not function when setting loco motor full load current
« on: September 13, 2025, 02:02:27 PM »
Good Afternoon All:

The saga continues:

I am doing a hard wire conversion of an ihc mehano 2-8-2 Mikado steam loco. 

The decoder is an LM-2S

From the nine pin wiring harness, I am using the red to the right side pick up, black to the left side pick up, orange to the positive motor, grey to the negative motor and blue and white for the front light.

Before installing everything, I did a motor test with the above connections soldered appropriately, with the exception of hooking up the front light.

I put the engine, without tender, on the test track. Hit find product; product found LM-2S.  Exit page.

Hit locomotives, hit no name engine, screen displays “button setup changed. Go to adjustments.”  Exit.

Hit adjustments, hit save, save complete, hit next page x2, hit motor full load current, use auto set yes, hit start test, count down, momentary display of 100% then showing 0mA, redo start test, loco speed 100% then error-timeout, try a third time, error time out.  The first two times the motor made a sound then stopped, the third time, no motor sound.

Thinking I had a short in the wiring harness, I got a new nine pin wiring harness and soldered directly to the terminals.  Same results.

Thinking maybe a bad decoder, I tried a brand new LM-3S.  Same results.

I put another dcc engine on the track.  Everything ran fine.

Thinking the motor was bad on my Mikado,  I hooked the motor leads to my dc power pack.  It ran just fine.  This motor is not the original motor.  The old three pole was shot so I replaced it with a new five pole.

What am I doing wrong?  Help.

Kind regards,

Max



gregeusa

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Re: Motor does not function when setting loco motor full load current
« Reply #1 on: September 13, 2025, 02:14:10 PM »
indications are that the motor was drawing too much current.

running a motor from a DC power pack does not indicate the current it is drawing...

measure the motor current...
Lots of tips and techniques on my site: www.elmassian.com contact me greg@elmassian.com

carpediem4570

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Re: Motor does not function when setting loco motor full load current
« Reply #2 on: September 13, 2025, 02:30:36 PM »
I hit the info button which took me to the loco info page. It states”motor full load current not set.”

The voltage reads 13.7 V with no motor current.

Is this what you were asking?

gregeusa

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Re: Motor does not function when setting loco motor full load current
« Reply #3 on: September 13, 2025, 06:08:57 PM »
NO

What you experienced when using the decoder looks like motor drawing too much current.

Then you hooked up to a DC powerpack and think the motor is fine.

You need to measure the current the motor draws ON DC, using the power pack, and see if it indeed is drawing too much current by itself.

power pack > through current meter > directly to motor, no decoder.

Do you have an amp/multi meter?
Lots of tips and techniques on my site: www.elmassian.com contact me greg@elmassian.com

carpediem4570

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Re: Motor does not function when setting loco motor full load current
« Reply #4 on: September 13, 2025, 06:56:25 PM »
Thank you for your reply:

Yes, I have a multi meter but I’m afraid I don’t know how to do what you are asking.  It makes great sense for trouble shooting.

As I said, this is not the original motor.  The unit came to me with a burned out motor.  This tells me there are other problems that caused the motor to burn out.

Kind regards,

Max

carpediem4570

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Re: Motor does not function when setting loco motor full load current
« Reply #5 on: September 13, 2025, 07:02:59 PM »
I have a second 2-8-2 that is new in the box.

I want to pull it apart and check the worm gear that turns the cog on the drive axle to move the wheels.  It appears this is quite stiff to turn and that might be why the motor can’t turn the worm gear.

Kind regards,
Max

carpediem4570

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Re: Motor does not function when setting loco motor full load current
« Reply #6 on: September 13, 2025, 08:06:51 PM »
Well, this certainly has been an adventure.

I pulled the cover off the worm gear and cleaned out all the old grease and it is moving much better.

The worm gear and the two wheel gears are plastic.  Do I need to regrade them, oil them or leave them dry?

The wheel axle have no bearings and ride in a plastic slot.  The axles are brass.  Do these Ned to be greased, oiled or left dry.

Thank you in advance for the help.

gregeusa

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I do Z scale and G scale... not an expert on HO mechanicals... sorry..

will tell you that you do need lubrication... I use oil on bearings, and jel grease on gears...
Lots of tips and techniques on my site: www.elmassian.com contact me greg@elmassian.com