HELP with electric roller shutters in a shop

[High Tower]

in that case, if it was me, i would put a 3 ph contactor on it operated by a normal switched spur

 

[telectrix]

nope, was me not thinking straight. was assuming common neutral, but then the neutral contact would have to carry the current of all 3 motors.DOH!

 

[gaz76]

so the three shutters are fed from 1 mcb? the 3 core and earth are probably just control cables, why not remove 2 of the switches and put all three cables onto one switch?

 

[Hawk81]

so the three shutters are fed from 1 mcb? the 3 core and earth are probably just control cables, why not remove 2 of the switches and put all three cables onto one switch?

What if the 3 motors running at the same time overload the circuit. What if the customer does not want all 3 shutters opening at the same time? Does not leave the customer with many options. If there is a fault with one motor then none of the shutters will work.

 

[Deleted member 26818]

in that case, if it was me, i would put a 3 ph contactor on it operated by a normal switched spur

Seems a little over the top when all that is being switched are low amperage switch feeds.

 

[gaz76]

the way i understood it was the customer wanted all 3 shutters working off one switch, meaning all three opening at the same time, surely if there was a problem with one motor the other two would still work?

 

[High Tower]

The point is NOT to open and close the shutters in one go....... its to ISOLATE all three shutters in one go, well thats what the op said, hence i would use a contactor as its not switching low current cables on the switch side, it could well be isolating while all 3 motors are on load, hence my design would be,

!x switched spur, fused down to give single point of isolation, operating the coil on a 3 pole, 3ph contactor, each pole isolating a different motor.

 

[Hawk81]

the way i understood it was the customer wanted all 3 shutters working off one switch, meaning all three opening at the same time, surely if there was a problem with one motor the other two would still work?

Not if the problem with 1 motor was throwing the mcb. Then no motors will work

 

[gaz76]

ahhh did'nt think about it tripping the breaker,

 

[Steve1412]

I may be simplifying things a little here but from what I read the OP want to isolate the roller shutters from an isolator. The shutters are on one circuit single phase. Surely just add up total load of motors and stick a DP isolator in the supply rated to cover all the load?????? Seems to be complicated for no reason.

 

[High Tower]

I may be simplifying things a little here but from what I read the OP want to isolate the roller shutters from an isolator. The shutters are on one circuit single phase. Surely just add up total load of motors and stick a DP isolator in the supply rated to cover all the load?????? Seems to be complicated for no reason.

That seems to be what the op is trying to achive, the only reson i suggested a contactor was that if this was employed then the isolator switch could be put anywhere.

 

[Steve1412]

That seems to be what the op is trying to achive, the only reson i suggested a contactor was that if this was employed then the isolator switch could be put anywhere.

I always find the simpler the better mate.....the usual pessimist in me would say if the coil on the contactor failed your not getting in the building!!!!!lolol

 

[High Tower]

Ha ha ha at least a passimist is rarely dissapointed!!

You have a good point with that though!!

 

[tonys]

I think they may be internal window shutters? very basic on the control side of things?

Also if the mcb failed you would not be getting in the building?

For the failing coil, just use a normally closed contact?

 

[Deleted member 26818]

Shutters generally use contactors to operate anyway.
Two per shutter, one for up and the other for down