Forkliftaction.com

DISCUSSION FORUMS : Forkliftaction.communicate

My forum profile

Printable version

Discussion Forums Home

Forum:

Mechanical Troubleshooting

Brand: Caterpillar - Model: M50

Number of messages: 12

START MESSAGE:

AlliedAir
Texas, United States

We have picked up an old Cat M50 Towmotor elec 36v forklift. It runs fine, but has only high speed. On low speed contactor pulls in but no action. Wiring diagram on gate is too dirty and faded to read. Any ideas, or where I can get manual or wiring diagram. Our local Cat dealer is not very helpful. (This unit is probably 1972 or so) We use the machine but it's a little dangerous to load stuff! Everything else on it works fine... Thanks.

Posted 22 Mar 2008 09:04 AM

Report this message

REPLIES:

Sort replies by

carl_v
Pennsylvania, United States

Serial Number please

Posted 26 Mar 2008 03:31 AM

Report this message

AlliedAir
Texas, United States

Model : M-50 Type; E , S/N 26N714.

Posted 26 Mar 2008 09:41 AM

Report this message

carl_v
Pennsylvania, United States

I'll look in my old manuals for info. Can scan and email. Need email address (abc at address dot com)

Posted 1 Apr 2008 05:51 AM

Report this message

AlliedAir
Texas, United States

Much thanks! [url/email removed] Other than that, any ideas what I would commonly expect to find wrong? The low speed contactor pulls in, and seems to pass power, but no action. Is there a gearbox or a two speed motor, or what? Thanks, Mark.

Posted 2 Apr 2008 09:59 AM

Report this message

AlliedAir
Texas, United States

I don't think it will let me post an email address. Our fax is 281-353-0704 email is alliedairtexas @ sbcglobal.net without the spaces...

Modified 2 Apr 2008 10:04 AM
by poster.

Report this message

AlliedAir
Texas, United States

Now I'm thinking about converting to a variable speed controller. Seems like for about $400 I can get controller and pedal. Any ideas about how to swap out? Also, anyone know if this motor is brush type or not?

Posted 26 Apr 2008 11:01 AM

Report this message

edward_t
North Carolina, United States

is the highspeed (bypass contactor) stuck? thins unit is/was a variable speed also does the bypass contactor pull in with the key switch.
this is MOST assuredly a brush type motor, but may be built before the days of a safety cutout for shorted electronic components we sometimes call PMT (for 'pulse monitor trip').
if you have decided to not deal with your local cat dealer,or any other electric forklift specialist, then changing out the controller to one you feel better about is a good option. you may also want to change or remove the need for contactors.
to change out the controller, you will primarily remove the control assembly and put the cables from the motor to the new places on the new controller, same with the wires from the trucks other inputs, you will need to know which cables come from the armature side of the motor and which come from the fields (also called the stator some times) and if you can not tell that this motor has brushes, that might be beyond your skill level, since knowing which cables are attached to the end of the motor with the brushes is how you will know which cables are the armature cables.

Posted 26 Apr 2008 09:41 PM

Report this message

AlliedAir
Texas, United States

I don't think the contactor is stuck. When you press the accel pedal some, you hear one click, but no action. When you press all te way, the high seed kicks in. I'm pretty certain this unit as Hi-lo speed only, and I feel that variable speed controller is the best solution. I'm confient that given correct instructions I could install the motor controller. The contactors are really pitted, and they priced out at $400-$600 each at Cat. I have also been trying to read the wiring diagram inside the electric cover (rear) but just aged enough to be unreadable. As far as locting th brush end of the motor, the problem is that it is under the center of the truck, and virtually impossible to see without lifting the truck. We got this truck for almost nothing, and use it only once or twice a week, so I don't mind spending a little money to make it reliable enough for occaisional use. The application sure doesn't justify a newer forklift, or a lease!

Posted 2 May 2008 09:30 AM

Report this message

carl_v
Pennsylvania, United States

Did you get the info I emailed to you? Thanks

Posted 20 May 2008 09:19 AM

Report this message

AlliedAir
Texas, United States

Sure did, thanks. It is not exactly the same as mine but pretty close. Yesterday was actually the first day I got to mess with it a little. Found a little glass fuse that was disentegrated but that still wasn't it. I am thinking the accel pot has failed like you mentioned. Probably will be a few days before I can look into it seriously. Thanks again.

-------------------------
Government contacting....

Posted 20 May 2008 08:23 PM

Report this message

AlliedAir
Texas, United States

Posted 20 May 2008 08:23 PM

Report this message

Forkliftaction.com accepts no responsibility for forum content and requires forum participants to adhere to the rules. Click here for more information.

FORUM GLOSSARY

Click for description.

FORUM

DISCUSSION

MESSAGES

NICKNAME

SIGNATURE

FORUMS

Discuss: Industry News & Whispers

Discuss: Conferences, trade shows & other events

Discuss: Mechanical Troubleshooting

Discuss: Technical arena. Did you know? Who knows?

Discuss: Machines. Forklifts, stackers, telehandlers, container handlers and reach stackers

Discuss: Business issues

Discuss: Safety, training & legislation

Discuss: Fun at work