2 speed fans

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m2oliva

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When installing a two speed fan that has two 3 phase feeds ,must both feeds be disconnected w/one single throw or can two seperate disconnects be used?This fan is in a cooling tower.
 
Re: 2 speed fans

IMO disconects to motors must open all the ungrounded conductors so a six pole disconect would be required for safety. That 2 speed motor is actually 2 motors inside a common case.
 
Re: 2 speed fans

Bob
I don't think section applies to 2 speed motors but motors supplied from 2 sources of power. Like an electric motor that is fed from the building and a generator. Just my humble thoughts.
 
Re: 2 speed fans

I do not know of a legal way to provide utility power and generator power to one motor without the use of a double throw switch.

I think this is for motors like the one in this post or motors that have internal heaters, fan motors, etc. on separate circuits.

Maybe some others will add their thoughts. :)

Bob
 
Re: 2 speed fans

Is there any reason you cannot use a three pole toggle switch to disconnect heaters (already fused in control panel)and pump with this switches instead of a disconnect switch?And is this double three phase single throw switch a commonly stocked item?
 
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