MCC Starter Replacement
MCC Starter Replacement
(OP)
Does anyone know if an existing across-the-line motor starter inside a motor control center bucket
can be changed to a 'soft-starter' without having any issues with NEC? Only wanting to change the
starter, not the breaker, control transformer, etc.
thanks
can be changed to a 'soft-starter' without having any issues with NEC? Only wanting to change the
starter, not the breaker, control transformer, etc.
thanks
RE: MCC Starter Replacement
RE: MCC Starter Replacement
Trying to cover all bases since I am bidding a project this week with this
combination.
RE: MCC Starter Replacement
RE: MCC Starter Replacement
I’ll see your silver lining and raise you two black clouds. - Protection Operations
RE: MCC Starter Replacement
" ....Does anyone know if an existing across-the-line motor starter inside a motor control center bucket can be changed to a 'soft-starter' without having any issues with NEC?...."
I look at it this way besides the NEC requirements consideration.
1. The existing breaker with magnetic only or with thermal magnetic is fine, as the Soft stater (SS) is equipped with thermal over-load with programable Class.
2. There shall be a contactor* ahead of the SS. Attention: The contactor* acts as an isolating switch when the SS is on stop state, where the SS motor terminals including motor terminals are "life! danger to touch" .
3. The SS shall be installed vertical. Observed the top/bottom and side cooling clearances and the volume of cooling air.
4. SS would require bigger bucket say > 3 time the size and say 2 time the weight of a DOL starter. Possible solution is to break up say breaker + contactor* in a different bucket. The other bigger bucket houses the SS starter in vertical position. The output of the breaker bucket is connected to the input of the SS bucket through external connection. This is to ensure/enable that the two buckets can be removed individually.
Che Kuan Yau (Singapore)
RE: MCC Starter Replacement
The customer wants a soft-starter on the existing pump.
RE: MCC Starter Replacement
RE: MCC Starter Replacement
RE: MCC Starter Replacement
RE: MCC Starter Replacement
RE: MCC Starter Replacement
We wanted to add a new MCC section.
The manufacturer quoted us a price around $20,000.
My boss sadly told me that price had killed the project.
I suggested that we had been quoted replacement price.
I suggested that I could match up a section of any manufacture MCC and cable connect it to the existing lineup.
I suggested going for competitive bids and stressing that this was to be new construction, not parts for an existing MCC.
The competitive price dropped to around $5000 and the project went ahead.
If you emphasize that you need a competitive bid and are not locked into one manufacturer, you may be able to buy a complete bucket, ready to plug and play for a very good price.
--------------------
Ohm's law
Not just a good idea;
It's the LAW!
RE: MCC Starter Replacement
RE: MCC Starter Replacement
- You cannot modify an MCC bucket and maintain the NRTL (UL) listing of the bucket, then the way MCCs work is that if any bucket in an MCC is not listed, the entire MCC listing is voided. NRTL listing of the unit will be important, either because the AHJ (inspector) will want to see it, or your company insurance policy will likely require it.
- There is a 99% chance that a unit space for an ATL starter will not be large enough to fit an equivalent Soft Starter. Ask the MCC mfr what the Space Factor is for a unit with a Soft Starter of that size, you will likely see a significant difference. Heat rise in MCC buckets is an important factor, regardless of the listing status.
To the other point about getting a quote, my experience is that if I need more than one bucket, I get a price on a "new" MCC as if it is a new project, not an "add on to existing". Your cost for a new MCC with those buckets in it will be less than the separate replacement buckets, and it will be shipped in what I call "handy steel shipping container" that you can throw away or find some other use for. MCCs are "loss leaders" for the equipment manufacturers, they lose money on them most of the time. So the plan is to make it up on the replacement or add-on units, knowing that you are "locked in" once you have their MCC. But any time there is a "new" MCC project, they are priced to beat the competition; whether there really is competition or not is something you keep to yourself. Even if I only need the one new bucket, I will sometimes throw in a couple of feeder breakers or starters to have around and spares. It still often comes out cheaper." We are all here on earth to help others; what on earth the others are here for I don't know." -- W. H. Auden