Vertical Lift Drive Train Questions

[jcoiner]

I am trying to quote the electrical interfaces for a customer who makes large doors (Blast and Containment type). They have a requirement for a vertical lifted door that is using a chain at each corner driven by sprockets. The chain does not appear to be a continuous loop. The sprockets are attached to shafts that are connected to a single gear box in the center to which an electric motor is coupled. Each shaft has a brake attached to it (I don't know what type) along with an electrical brake in the motor. Several questions are raised...
1) Can the motor back drive the chain to lower the door.
2) If back driving, can the motor hold the door or are the brakes required to be on.
3) Are the brakes just on/off or do they need to be controlled (i.e. speed control of the door when lowering).
4) A chain snarl detector is specified, would it have electrical interfaces?
5) Is there prior art or text book standard for this type of drive?

Any help or direction to understanding would be greatly appreciated. Thanks.

 

[jbartos]

Suggestion to the original posting marked ///\\\: 4) A chain snarl detector is specified, would it have electrical interfaces?
///If it does not then the motor overload or overcurrent protection will have to trip. To avoid those trips, the electrical e-stop interlock is recommended.\\

 

[jbartos]

Small encore: Visit

http://www.usace.army.mil/inet/usace-docs/armytm/tm5-692-1/chap32VOL-I.pdf

etc. for more info.

 

[jbartos]

Suggestion: Another approach could be given some consideration, e.g. application of linear motors to avoid chains and improve reliability, availability and safety.