22Kw motor isolator

[Jc1996]

I’ve got a temporary 22Kw motor running on a 63amp isolator. Think the isolator is rated AC3 for 11Kw . If the isolators not being used to switch the load is this okay?

 

[steptoe]

No

 

[tinman1973]

Is it DOL or star delta with a 6 pole isolator?

 

[roys]

Is it DOL or star delta with a 6 pole isolator?

Does anyone still use star delta starters now other than training centres as an exercise in contactor control.
I have been in industry since 1981 and the last one I saw in proper use was the early 90’s I think and that plant is flattened now.
Edit.
I have just remembered, I saw one in an Eastern European wood mill about 10 years ago, age is effecting my memory, but there can’t be many star delta starters left.

 

[revjames]

Does anyone still use star delta starters now other than training centres as an exercise in contactor control.
I have been in industry since 1981 and the last one I saw in proper use was the early 90’s I think and that plant is flattened now.
Edit.
I have just remembered, I saw one in an Eastern European wood mill about 10 years ago, age is effecting my memory, but there can’t be many star delta starters left.

There are still a few where I work, water pumps, compressors, capstan winch to name a few. Still a good solution in some environments

 

[Jc1996]

It was on a motor circuit with a soft start,sorted now. Just a question I was curious about as I’ve seen plenty of isolators fitted for motor circuits that aren't AC3 however the continuous current is rated for the circuits protection device.

 

[Sidewinder]

The isolator should be rated at circuit current.
The breaking capacity depends upon the application.
If it’s red/yellow then it needs to be able to break full circuit current at AC23.
If it’s black/grey then AC21 would be fine.

 

[Jc1996]

When you say rated current that will be the current it can safely switch right(AC3 or AC23 current rating)? Not continuous current?

 

[Sidewinder]

For black/grey it should be circuit current rated, the AC21 rating is not so important because it is for routine isolation for maintenance only, therefore should only be operated when the circuit is not under load.
For red/yellow the AC23 rating should be motor/circuit full load current as it is for use under emergency switching condition which means it must be able to break the full load current.
That is what the red/yellow actuator denotes, that the unit is suitable for emergency switching and emergency isolation under normal and abnormal conditions.
Whereas the black/grey actuator indicates that it is an off load isolator for routine isolation only, not for use under emergency situations.