Scott 35 said some time ago that he had some info on the use of resistors to control the speed of a overhead crane motor. If you do could you post them or e-mail them to me? I have 2 weeks vacation and would have the time to study them before i go back to work. I would really like to have a better answer for the boss than, "it appears to be ok electrically, don't know why it's not working?!" Thanks, spkjpr.

What type of Information are you looking for? Typically on the old Cranes the hoist drive was either a wound rotor motor (AC) with a drum or rheostat controller or a DC Motor and Controller that had either a step type series controller or a drum controller with stages of grids. The newer ones typically have some type of Electronics control (Tube type or solid state) interfaced either in a DC controller or the rotor circuit of a wound rotor motor.

I have been retired for about 6 years so I have purged many of my prints but I may be able to find some information if I knew specifically what you are looking for. If you can specify what type of system you have and if dynamic and/or regenerative braking is involved I will look through my old information and see if I can find something that might be of help to you. In your application do you also use bridge and carriage drives?
If you have multiple drives do they all use the same technology?

Tom R.

Tom,

Could you scan and E-Mail a few of your Schematics, so I can draw them in AutoCAD then post here?

I can easilly draw up and post simple Wound Rotor Schematics, but it would be nice to have more precise details to add with the drawing which relate to Cranes.

If you can scan and send, save as .GIF or as .JPG with compression [or use PKZIP].

Send to me at:

adst at pacbell dot net
[phonetically spelled out to avoid lurking spambots ]

Thanks!!!

Scott SET

Tom r and Scott. The motors in question are wound rotor AC with no dynamic braking. We have 3 different P&H cranes that all use this system. Thanks guys, I'll keep checking here in between Christmas parties.