3 phase motor

[mmelectrics]

Hi all

Its not often i work with 3 phase so am looking for a bit of advise on cable and circuit breaker size. I have a job to install an isolator for a motor extraction in a small spray booth getting installed in a workshop. I was planning on using 2.5mm single core cable in already installed metal trunking with a 6A type c triple pole circuit breaker. The detail i have on it is
500 BDA
[email protected]
1.5kw motor
2640rpm - 2pole
400w 3 phase 50hz
d90s
FLC 3.0A
SC 21A

 

[LeeH]

Not a chance that CB will hold.

Show your calcs on how 2.5mm2 came about too.

 

[davesparks]

How did you calculate the mcb size and cable size?
What did the manufacturer say when you asked them what supply they recommend?


Sent from my iPad using Tapatalk

 

[TJ Anderson]

Cable size is fine for that load. You could go C16 for OCPD if Zs is satisfactory. That fan will spin up quick so start current will be very short. C6 would be fine. Your data states a starting current of 21A with a running current of 3A.

 

[TJ Anderson]

Also you will want a DOL starter.

https://inverterdrive.com/group/DOL-Starters/WEG-DLW-1-5kW-Direct-On-Line-Starter/

 

[telectrix]

wot he said.a dol with overload and use a C16 MCB.

 

[David M]

Wot they said. ^^^^
If your ZS is ok the C16 will be ok for short circuit and overload protection of the supply. Then stick an isolator near the motor with a suitably rated DOL which comes combined with an overload device which is suitably rated for the motor.

 

[mmelectrics]

Thanks for your replies a will get a c16 breaker, I am only wiring and installing isolator supposedly

 

[davesparks]

Thanks for your replies a will get a c16 breaker, I am only wiring and installing isolator supposedly

If you are only installing the supply then get the person who has designed the supply to give you the information you need.


Sent from my iPad using Tapatalk

 

[Marvo]

Don't try to protect the fan with the MCB, protect the circuit with the MCB and use a DOL starter or manual motor starter to protect the motor.

 

[spary]

hope it's not a hazardous area before everyone tells him what gear to use lol