Hoist Motor & Electrical Protection

Most of the protections are built into a quality hoist motor internally.

If it has a nameplate, those are the minimum requirements.

If it doesn't have a name plate, don't use it.

What are "upstream devices"?

You should provide bimetallic thermal relay for overload protection and HRC fuses for short circuit protection. O.L Relay can be of Siemens make and HRC fuses of English Electric make, both are reliable brands. More over you have to select the Hoist of suitable rating to suit your application. They are available as medium, heavy and steel mill duty ratings.

Hoist motors are compound wound or series wound for maximum torque from a dead start. This is why they draw huge power at startup and should have internal overload protectors for speed,power, and heat to achieve a government safety rating. The maximum current draw should be on the specification plate attached to the motor which is required by law. Shunt wound motors tend to be rated for continuous duty whereas series wound motors do not because of overheating and speed issues. Check out types of motors in an electrical engineering handbook or on internet.

He said in the beginning of his post that they are AC motors, not DC.

I am not an electrician most of crane information comes from "after the disaster" safety meetings. I am a tool and die maker who has to rely on the crane. Cranes and all other lifting devises have huge government safety regulations defining construction, installation, maintenance, certification, and use. Penalties for violating the regulations can be quite severe.

Thanks

I agree that name plate takes care of standard protections required under manugacturers' and code guideline. Those guidelines normally address safety and equipmentprotection. Without being specific to a project, I was wondering whether there are additional considerqations for supply feeder to equipment such as hoist, elevator, etc. which are intermittent duty, but high frequent torque cycles. Supply feeder encompass switching equipment, cables and protective devices.

For example- which one is better - fuse, breaker or MCCB? Any starting considerations such as volt drop for enhanced life and performance of installation?

All the applications you mentioned are industrial. I am not an electrician or electrical engineer. Where I have worked all the applications you mentioned always used industrial "Slow Blow Fuses" to handle the start up power surge. Most electricians do not like using circuit breakers for these applications because the breakers tend to stick with disastrous consequences.

For Hoist motors duty calculations are as per AC4 duty. for selection of starters use TYPE2 coordination as well define the life of starter while selecting.

Any idea, how I get guide to AC4 duty calculation?

I assume it is European standard

Please refer to IS:3938 for Wire Rope Electric Hoist for various duty conditions.