Protection for VFD with MCCB
Protection for VFD with MCCB
(OP)
Hi
Got a question, for those who use European standards. Question is at quotation level. I got to protect VFD, with MCCB. Designer asked for 50 KA, coordination type 2, and both thermal(0.8-1 In) and magnetic protection. After u, can i use class 10 of thermal protection, with MCCB for motor protection (Surion type-GE, )? Designer wants curve C, but this is nonsense. Curve C is for MCBs only, and at 50 KA (and for some cases 200 A), theres no MCB.
Thanks for reply .
Got a question, for those who use European standards. Question is at quotation level. I got to protect VFD, with MCCB. Designer asked for 50 KA, coordination type 2, and both thermal(0.8-1 In) and magnetic protection. After u, can i use class 10 of thermal protection, with MCCB for motor protection (Surion type-GE, )? Designer wants curve C, but this is nonsense. Curve C is for MCBs only, and at 50 KA (and for some cases 200 A), theres no MCB.
Thanks for reply .





RE: Protection for VFD with MCCB
RE: Protection for VFD with MCCB
AB, ABB, Siemens, Telemcanique/SquareD, and others should be able to accomodate those curves.
Just stay clear of Moeller.
flash
RE: Protection for VFD with MCCB
The same curves are not available on a MCCB although an MCCB with an electronic tripping unit should be able to give at least as much flexibility in setting the tripping characteristic. Where's the problem?
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If we learn from our mistakes I'm getting a great education!
RE: Protection for VFD with MCCB
RE: Protection for VFD with MCCB
I would have to pull out my copy of UL 508E to see if Type 2 coordination applies to VFDs. I know it does apply to contactors. I also thought that the combination had to be tested in order to qualify as Type 2 coordinated.
I would use either a MCCB or a MPCB to protect the VFD. If you look at A-B VFD manuals they list the recommended protection for each type. I would assume that other manufacturers of VFDs do the same. A-B's 140M is listed for Type 2 coordination with their Bulletin 100 contactors. I don't know about other manufacturers ratings.
The designer may have specified it wrong which isn't uncommon.
RE: Protection for VFD with MCCB
MCB = Miniature Circuit Breaker in IEC land.
These are two different things. I believe Scotty's assessment is correct, since the OP referred to European standards.
In the US, it would be a code violation to use an MCP upstream of a VFD to protect it, since an MCP can only be used as part of a combination starter for control of a motor.
RE: Protection for VFD with MCCB
RE: Protection for VFD with MCCB
dpc
RE: Protection for VFD with MCCB
FAQ237-1402: What do all the different terms mean when discussing circuit breakers and how are NEMA and IEC terms different?
JRaef.com
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RE: Protection for VFD with MCCB
ScottyUK : I expected from the projector something what makes sense, not curve type C for MCCB. U really can get close to this curves A B C D , with an electronic trip unit(anyway in practice no-one did that before). And for MCCBs there are trip classes: 5(for "light" loads), 10A, 10, 20, 30(last onme for heavy duty).
RE: Protection for VFD with MCCB
Don't expect something to make sense from the specifier unless they know the standards. Besides Type 2 coordination does NOT apply to VFDs as far as I can tell (it is meant for circuit breaker/motor starter (contactor) combinations) and the two components must be tested together to verify that they meet Type 2 coordination (i.e. no damage so that the contactor can be used again after a fault). See http://ww
Regarding MCB's, has anyone seen a 3 pole Miniature Circuit Breaker rated for 480V and UL 489 rated (so it can be used ahead of a motor contactor)?
RE: Protection for VFD with MCCB
RE: Protection for VFD with MCCB
RE: Protection for VFD with MCCB
JRaef.com
"Engineers like to solve problems. If there are no problems handily available, they will create their own problems." Scott Adams
For the best use of Eng-Tips, please click here -> FAQ731-376: Eng-Tips.com Forum Policies
RE: Protection for VFD with MCCB
I know you can get an electronic tripping unit to behave in a similar manner to the MCB curves. The tripping classes you refer to are specific to MCCBs which are intended for motor protection duty. The tripping class is more commonly found on a thermal overload relay.
Type 2 coordination has already been discussed above by the NEC guys. I wonder if the 'C' referred to is the setting for magnetic trip element? On breakers where it is adjustable the settings are (from memory) designated by letters from A-H. A setting of C would be a fairly low magnetic trip setting.
jraef,
LOL.
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If we learn from our mistakes I'm getting a great education!