Combing MCCB with Manual Motor Controller?

[ElectroWeed]

Hello everyone,

I am looking for a manual motor starter combined with a circuit breaker in one package.
As an example, Sprecher+schuh have a model KTA7 that they claim has all the functionality of a typical MCCB, Contactor & Overload combination all-in-one package. I've never seen this before and I find it hard to believe, but I'm wondering if anyone has used one of these before. Automation Direct also sells another example (made by Fuji).
I need to meet UL/CSA standards also.

Any experience with these types of motor controllers would be greatly appreciated.

Thanks.

 

[dpc]

A properly sized thermal-magnetic molded-case circuit breaker (MCCB) all by itself can be used as manual motor starter, at least in the US.

 

[ElectroWeed]

In Canada, a motor starter must be used on any motor larger than 1/3hp. I should've stated that I am using a 1hp motor in this case.

 

[macmckim]

All you need is the manaul starter as your in coming electrical service should already have a breaker in the panel. The breaker will cover any short circuit issue and starter handle the motor starting and protection.

 

[jraef]

Those are called Motor protective Switches here in the US, and are available now from almost all of the motor control component suppliers. All are UL listed, but the UL listing is as a manual motor starter under UL508, not as a circuit breaker under UL489. As such, they must have a listed SCPD (Short Circuit protective Device), either fuses or another listed circuit breaker in front. The manufacturers usually provide the UL useage information in their catalogs so that you know the maximum size of CB that you can use it behind.

"Venditori de oleum-vipera non vigere excordis populi"

 

[rbulsara]

I am with dpc.

MCCB has both elements, overload (thermal or electronic) and short circuit (magnetic or instantaneous) which when meetig requirement of a motor protection per NEC, can be used as a manual starter. (in USA)

Also in the USA there are manual starters with thermal overload protection with or without pilot lights are available, which is essentially a MCCB with a light.

jraef:
Unless we are talking about two different items, I beleive MCP or moldes case switches havemagnetic trip only but does not have thermal trip unit (overload). The magnetic trip is the short circuit protection. Overload is protected by separate O/L relay in starters.

MCP or molded case switches can not be used alone as a motor protector, you need separate thermal overload protection, hence they are only used in combination motor controllers.

macmckim: What you are suggesting will only work if the service size is not more than 250% (in most cases) of the motor FLA.

 

[jraef]

I am very familiar with them, I have used them extensively and I think they are a welcomed addition to the US market place from the IEC world. I never used the term MCP, I said we call them Motor Protective Switches (MPS). The term MCCB has no meaning in the US, and causes a lot of problems here when it is used. The conventional wisdom has been to not adopt the term becasue of possible confusion with MCC, and CB, both of which have clear meanings here.

The point I was making was that although they can be used per IEC as both the short circuit device and the thermal OL device, here in the US SCPDs must be either fuses, or UL489 circuit breakers. Since these devices are neither, accommodation was made for them in UL as manual motor starters, but they still need to be backed up by a listed circuit breaker or fuses.

"Venditori de oleum-vipera non vigere excordis populi"

 

[rbulsara]

jraef:

We are talking about two different things as we both are correct.

What you are talking about this is on this link:

http://www.bihplat.com/english/seguridad/

What I am talking about is this link:

http://www.squared.com/us/products/...5256B05004B544F/$file/combostrtrsFrameset.htm

If my link truncates, its a squared.com site , and go to prdcuts and look up combination starters with circuit breakers, which also discusses MCP.

 

[RRaghunath]

There are also Motor Protection Circuit Breakers (MPCBs) available for the purpose intended.

Please check Siemens website.

L&T (India) also has similar devices for small range motors in their range.

 

[jraef]

I was thoroughly confused and retract my earlier statements (can I do that?). Apparently I am behind the times on this issue becase I found that the term MCCB has in fact been adopted into the lexicon of US suplliers, and it means Molded Case Circuit Breaker. I had learned that term years ago as Motor Control Circuit Breaker.


Never mind...

 

[ElectroWeed]

Thanks guys for all your responses to my question. After reviewing your comments and reading an application guide provided by Sprecher+schuh, I have come to a conclusion. The bottom line is, these devices cannot be used in North America without additional breaker or fuse protection upstream.
If anyone is interested, the application guide written by Sprecher+schuh is an excellent read on this subject. It can be found on their website under library-catalogs-section F-page F77 to F82.

Thanks,