CSA circuit breaker standards
CSA circuit breaker standards
(OP)
I am building some equipment for use in Canada and it must comply with CSA. The motor/reducer being used is 42VAC/3PH and will be controlled by a VFD. The data plate on the motor shows 4.9 Amps with a SF of 1.0.
I don't have a copy of their code, but will purchase one as a last resort as we seldom do work for Canada. Hopefully someone here on the forum has one and can help.
Does their code state what size the circuit breaker should be?
Thanks,
Paul
I don't have a copy of their code, but will purchase one as a last resort as we seldom do work for Canada. Hopefully someone here on the forum has one and can help.
Does their code state what size the circuit breaker should be?
Thanks,
Paul





RE: CSA circuit breaker standards
I would treat the VFD as a piece of electrical equipment with no special starting requirements and protect it accordingly.
The CEC generally accepts a 15 amp breaker as adequate protection for any normal load that would otherwise require a smaller rating.
Is anyone else able to add to this?
I believe that the Canadian Electrical Code is available for purchase and download online. Found under Canadian Standards Association.
For DOL starting of a three phase induction motor, a 15 amp breaker is acceptable for any motor up to 9 amps full load current.
Bill
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"Why not the best?"
Jimmy Carter
RE: CSA circuit breaker standards
However, you may consider using high speed drive fuses in a smaller size for better short circuit protection for the drive. Check to see what the drive manual recommends. Its recommendations will also comply with the CEC as long as the drive is CSA/cUL rated.
RE: CSA circuit breaker standards
Thanks.
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: CSA circuit breaker standards
RE: CSA circuit breaker standards
If you are sending a design to be field built this standard is applicable.
If you are building and shipping the panel then other standards apply. In your position I would consider sending my design to a control panel building shop and have them build and certify the panel. If your shop has authority to certify panels you you can probably get the certification accepted in Canada.
You may have to apply for a local inspection and approval. The local approvals I have done were cheap, easy and painless.
In most instances the approval from another jurisdiction was accepted. The one exception was the flexible supply cable to a large dough mixing machine. The inspector passed the machine but required us to replace the flexible cable.
There was a reasonable fee for the inspector to attend the site and approve one machine. A further charge of about 20% for each additional machine to inspect at the same time.
That was some time ago. Does anyone have more recent experience??
Bill
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"Why not the best?"
Jimmy Carter
RE: CSA circuit breaker standards
As far as I can tell, there is no specific rule for VFD's so I used the generic 80% rule. This is backed up by the recommendations of Allen Bradley for the minimum fuse sizes for their drives, which are CSA labelled.
For instance, for a drive with an input rating of 93A, they recommend a minimum fuse size of 125A and a maximum non-time delay fuse size of 375A. The maximum size is apparently chosen to comply with CEC 28-200, but I see no reason to size a fuse this large for a drive. Some suppliers I have dealt with will recommend sizing fuses in the 150%-200% range to reduce the risk of nuisance tripping, however.
In my opinion, there really should be a section in the CEC specific to drives. It seems odd to treat them as regular motor branch circuits.
RE: CSA circuit breaker standards
RE: CSA circuit breaker standards
Our partner in this project is providing the VFDs and might be driving multiple barrels with one VFD. My guess is that they will put a circuit breaker between the VFD and each of the barrel stations. If the gearmotor is rated at 4.9 Amps, what size breaker will they need?
RE: CSA circuit breaker standards
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: CSA circuit breaker standards
RE: CSA circuit breaker standards
http://search.rockwellautomation.com/search?q=IC-A...
David Baird
Sr Controls Designer
EET degree.
www.afctool.com
RE: CSA circuit breaker standards
RE: CSA circuit breaker standards
VFD's are normally acceptable for overload protection. However, when running multiple motors from a single VFD, separate protection is always required since the VFD O/L trip must be set higher than any of the individual motor current ratings.
RE: CSA circuit breaker standards