Time-delay between starting of multiple motors

[RalphChristie]

I have asked the question in the Electric motors & motor controls engineering Forum:

See the original question in thread237-136811

I would appreciate it if anyone can give his/her comments on the time-delay between two or more motors during start-up (for a conveyor) from a mechanical viewpoint. (Each drive a motor-gearbox combination)

The question is answered from an electrical viewpoint but I would like to hear what you think from a mechanical perspective.

Many thanks

Regards
Ralph

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[unclesyd]

Not much into large multiple drive conveyors but here is a system that I’ve seen used on some very large conveyors with multiple drives. We use this unit on on 2 70' metal chain bucket elevators.

http://www.howdenbuffalo.com/Products/gyrol.htm

 

[RalphChristie]

Thanks unclesyd:

However, the same question would apply to multiple drives with fluid-couplings: Are there any delay necessary between the start-up times of the different drives from a mechanical viewpoint? From an electric perspective the time-delay can be very short, but not simulataneous, due to the high inrush-currents. (0.2-0.5second delay) Any reason/s for a longer delay mechanically?



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[unclesyd]

Sorry I can't be of anymore help.
Like I said I'm not a conveyor person. As stated I saw this type drive on some very large multiple drive conveyors. Recalling some of the conversation at the time I recall that there was a big concern about the load on the belts themselves, especially the splices if an older belt. All the conveyors were in operation when I visited so I didn't get to see a startup. I do remember that the outlying belts were run form one substation so I would presume that the electric component was a big consideration in choosing the drives and the startup sequence.

Howden Buffalo used to have a very good technical section so you might give them a try.

Anecdotal:
The mine that I visited several times and where I saw these conveyors has gotten gigantic and they have become paranoid about publicity. My brother and I stopped on a public road to take a few pictures of the mine and were immediately run off by armed cowboys in black fatigues, bloused boots and big guns riding in black four wheel drive pickup.

 

[RalphChristie]

Thanks unclesyd:

The mine where I am working is also big with some impressive equipment, but normally it is quite easy to arrange a visit. I believe here is also a lot of cowboys, luckily not with guns! (and that is maybe a very good thing..)



I have heard one mechanical reason for a longer time-delay between multiple motors starting a conveyor. If you/someone are interested in it, check my reply on 20 Oct. in the original posting. (thread237-136811)

Thanks again for your reply.

Regards
Ralph


[red]Failure seldom stops us, it is the fear for failure that stops us - Jack Lemmon[/red]

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