ECN Forum Forums Technical Discussion Electrical Theory and Applications WRM controllers

Scott35:
I was looking at your drawings on WRM but did not see any control for these drawings.
Are they supposed to drum-type controllers ? or run from the ground via push-buttons ?
I worked on a lot of AC cranes with this type of set-up but I never seen one with a DB for this type of application. Especially with overhauling loads and large gear-boxes.
A lot of them use Regenerative braking and if that failed the operators would reverse the controller in an emergency situation.

WOC

WOC,

I can't remember where that schematic came from, but it was a very basic item!!!

If you could pass some more in-depth stuff my way, I would really appreciate it!!!

Scott35 S.E.T.

This appears to be the same type I once ( and only once ) worked on in the late 60's.

The overhead crane was operated by a pendant control.

As I remmember, under heavy loads, the the actual down button was a 'low step control ' up.

If I remmember correctly the system was called "MagnaFloat"

Scott
What are you looking for I have some older drawing of the controllers., with DB and plugging control and frequency acceleration relays.
The older models were really neat as compared to how it is done today.
One manufacture was the Paulings and Harnishfeger and there cranes were all Wound rotor motors with huge gear boxes with mechanical brakes with clutches on them to allow slip and plug stopping and reversing.
The scary thing is when the load is rated more than the crane, the operator has the hoist going up but the load is still coming down and generally they would burn up the resistances of the hoist motor. But the motor was usually fine.

WOC