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PMG retrofit to Stamford alternator

PMG retrofit to Stamford alternator

PMG retrofit to Stamford alternator

One of many things I'm responsible at work for is a 500kVA diesel genset which I inherited via my predecessor. It isn't a particularly well-specified machine for the job it is doing - standby duty - but I'm toying with retrofitting a PMG in lieu of the bus-fed excitation to improve its fault-clearing capability. The alternator has a cover which, when removed, would allow access to the outboard end of the shaft which I believe is machined to accept an adaptor or coupling to a PMG.

Brief inquiries have drawn a blank in terms of OEM parts for this machine, and because it wasn't originally supplied with a PMG Stamford aren't being overly helpful in converting it. I understand why, it's just a little frustrating too. I can probably obtain a PMG for a similar set and have an adaptor ring manufactured if needed. Has anyone done anything similar in the past?

RE: PMG retrofit to Stamford alternator

When I was at Brush, the original turbogenerators from late 60's on had a Newton Derby PMG, sat on a stand at the end of the main brushless exciter. This was coupled to the exciter by a small flexible coupling. When this failed, customers found that a length of garden hose was a satisfactory engineering solution, secured by a couple of terry hose clips!

The PMG was small, say 6-inch diameter and 6-inch long. This for a 30MVA generator. Later we developed an integral pmg system, I think.

Newton Derby are still there, and part of winder. their website says they can do excitation solutions, so give them a try http://www.winderpower.co.uk/product/rotating-mach...

RE: PMG retrofit to Stamford alternator

What is the model number of the generator?

RE: PMG retrofit to Stamford alternator

Thanks Hoxton,

We already deal with Winder Power on the transformer side of the business, I will inquire whether they can help us.

Genhead - will have to find out, not at work right now.

RE: PMG retrofit to Stamford alternator

I have done it a number of times, in sizes similar to your unit, as asked above, can you provide specific info on the unit you have? For some reason since Stamford got bought by Cummins these type of inquiries seem to not get much attention, at least in the USA.

Here is a link to their customer service, service-engineers@cumminsgeneratortechnologies.com

I think this is still the factory authorized Avk/Stamford house in the UK, r.taylor@baumuller.co.uk or mail@baumuller.co.uk

I've used these guys in the US to get parts for most of the smaller (less than 1MW) units I run across, http://www.dieselgeneratorsmiami.com

If you do retrofit a PMG I would suggest you consider adding set of fuses or a breaker on the PMG output, Stamford does not protect the output of their PMG's and I find in many cases a failed AVR also results in a toasted PMG. I had an interesting discussion with a Stamford engineer on the subject at PowerGen last year. Maybe they just like selling the parts. I do it pretty much anytime I replace an AVR or PMG.

Hope that helps, MikeL

RE: PMG retrofit to Stamford alternator

Let us know what happens Scotty, please.

RE: PMG retrofit to Stamford alternator

As an alternative to the garden hose, you may consider belt driving the PMG.

Quote (Hoxton)

Let us know what happens Scotty, please.
Second that.

"Why not the best?"
Jimmy Carter

RE: PMG retrofit to Stamford alternator

Certainly will gents. It's school holiday week over here, I'm enjoying spending some time with the kids and I'm not back in the office until next week. smile

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