Help on motor control please

Harwoodandy · Jun 4, 2015

Looking for a bit of advice please. Commercial kitchen, extract system. 2 motors (both single phase). One brings fresh air in the other takes dirty air out. Motors are in a plant room on a different floor and have local isolators. Speed controllers on both motors in the kitchen. Motors are rated at 4A and 7A respectively.My question is, how to comply with Regs 552? around starting (remotely sited) and does the overload protection have to be thermal overload as in a DOL starter or would a fuse/breaker suffice? 537.5.4.1 also tells me that manual restarting is a requirement. My concern would be that a breaker trips, chef goes of to plant room to look and removes cover to fan, other chef goes to basement and resets breaker - chef in plant room, well, you can summise the rest. Any suggestions to most cost effective solution would be appreciated, bearing in mind there are 2 motors as well. Also for some reason I cannot put carriage returns in this post so sounds like i'm gushing!!. Thanks in advance Andy

telectrix · Jun 4, 2015

that's why there are local isolators for the fans. chef isolates before sticking head in fan.

snowhead · Jun 4, 2015

Possible slight over thinking by the O.P here I believe.

Could be a case of too many Cooks....

The Dead Chef;

Shouldn't have been in the Plantroom.
Should have needed tools to remove the fan cover, if not it should have interlocked safety switches.
If he / she has access to tools they would have been deemed competent.

The Plantroom should have been locked with access restricted.

There are millions of fans in similar situations and hardly any dead Chefs.

davesparks · Jun 4, 2015

You would not normally use an mcb for motor overload protection, you would use a motor overload protection unit of some type. Possibly a motor protection circuit breaker or a thermal overload unit/relay included in the starter for small motors like that.