Main Motor Problem

Hi Guys,
I'm a new member, but have got great advice from all of you over the past year.
I have a 1994 L428, just yesterday i was on a make ready,just took sheet out for inspection when i heard the machine stutter. Turned off straight away, did the normal checks, inching the machine. Then went to stage 1 crawl, nothing, then stage 2, nothing. Then to run at 3k, 4k,5k-8k, then machine slowed down by itself then speeded up and then back down. Pressed stop button. Now it only goes to stage 1 crawl, amps nearly 80, shuts down, no1 error on console (Main Motor), tech guy told me to go to Inverter (VF61v) press reset. This does clear it to run but only, 1 stage crawl, Error on Inverter console says, Ot, Over Torque, NS = 42 rpm,NB = 0 rpm,Io = 78.4 [A]. Tech guy coming in tomorrow, but he says I'm in serious trouble, he says its 1 of 3 things: 1.main motor , 2.Main motor Encoder, 3. Drive unit. Any Ideas?

 

It is being encoder troubles.
not big trouble,easy solved.
I had duplicate problem on my machinen.

 

Thanks for easing my mind, engineer ordered the part this morning, he says he is 90% sure its the encoder, if not he says the Vf61 Inverter.
Fingers crossed!!

 

Defiantly the encoder, but first check it and make sure the Allen screw did not come loose, mine did just the same thing. Remove the cover on the motor, the encoder is right there. Check for slippage, if there is any remove the allen add lock tight and reinstall and all will be good. a new ecoder is pretty expensive.
John

 

I had a similar problem before as well, it ended up being the speed control pot. burned out. replaced it and the problem went away.

 

Had almost the same problem on our LS440 and it turned out to be the encorder. We just replaced it & all was well. I have a spare one if you need one.

 

It was the encoder, half an hour job. Machine grand now. A bit expensive though. Thanks for all your help.