Paralleling larger MEPs

[Krc002]

Hello all,

Has anyone here ever paralleled two of the larger MEP sets? i have seen sewerzuk parallel a couple of the smaller ones, but i am looking for anyone having luck paralleling two 30kw sets. i need 60kw or so total, and already have one 30 kw set. i am wondering if it would be easier and safer to have one set, or more cost effective to buy a second 30kw set and parallel them to get what i need as i already have almost half of that equation and i wont need 60kw anywhere near as often as 30kw and it might be nice to have two sets to alternate use. also, is the paralleling gear on these sets truly designed to share a load like that, or to just bring them both online to shut one down for maintenance?

Any thoughts would be much appreciated,
KRC002

 

[1800 Diesel]

Hello all,

Has anyone here ever paralleled two of the larger MEP sets? i have seen sewerzuk parallel a couple of the smaller ones, but i am looking for anyone having luck paralleling two 30kw sets. i need 60kw or so total, and already have one 30 kw set. i am wondering if it would be easier and safer to have one set, or more cost effective to buy a second 30kw set and parallel them to get what i need as i already have almost half of that equation and i wont need 60kw anywhere near as often as 30kw and it might be nice to have two sets to alternate use. also, is the paralleling gear on these sets truly designed to share a load like that, or to just bring them both online to shut one down for maintenance?

Any thoughts would be much appreciated,
KRC002

Haven't done it myself but will be attempting the parallel setup on two MEP-004As in a few weeks. TM has a fairly straightforward procedure to follow. Shouldn't be a problem.

When paralleling the generators they do actually share the load. Haven't looked into shutting one down for maintenance though, but don't expect that would be a problem....

Read up on the process outlined in the TM and follow the instructions. I would definitely go for the parallel setup, vice using a 60 watt unit--especially if you only need 30 KW or less for long periods.

Just out of curiosity, have to ask why the 60KW is needed? I've been considering getting a 30 KW myself but it would be for a friend's seafood business.

Good luck with the plan,

Kevin

 

[Munchies]

I've been considering getting a 30 KW myself but it would be for a friend's seafood business.

You and me both! Have a job in Lousiana in a month or two for two mep-007B's at a seafood place on the intercoastal.

 

[Krc002]

I appreciate the reply, i have been reading over the manuals, and have a pretty good understanding of how it goes. I was looking for some verification from others before attempting the procedure and coming up with the connectors and a diagram for making the cable to parallel them. but it all sounds good and very doable.

I need around 60kw of 460v three phase in my woodworking shop to run a wide belt sander and the dust collector and air compressor that need to run at the same time as "support" to the sander. the wide belt has a 40hp main motor which is the largest in the shop and i think with my compressor and dust collector running at the same time i should be at just about full load if i am running wide tables or doors through the machine. it would be nice to start that motor on both sets and then shut one down once its running to save fuel when i am working up smaller pieces, and this sounds pretty doable as well.

Kevin,
Once you attempt to parallel those 004s, if you want to make a post or reply to this thread, that would be greatly appreciated as id be interested in seeing your lessons learned.

 

[Triple Jim]

I know you know more about your requirements than I do, but it might be cheaper to set up a soft-start for the big motor so you don't need 60 kW to get it running. 40 hp is only about 30 kW at full load.

 

[Munchies]

I know you know more about your requirements than I do, but it might be cheaper to set up a soft-start for the big motor so you don't need 60 kW to get it running. 40 hp is only about 30 kW at full load.

Or possibly a VFD? I only know what smaller ones cost though.

 

[glassk]

[h=1]Sizing Gen-Sets For Large Motor Starting[/h]Feb. 1, 2000 Larry A. Bey, Cummins Onan Corp

VFDs require larger generators.





All versions of variable frequency drives (VFDs) are current limiting and reduce starting kW and kVA. The current drawn by these drives is nonlinear (having harmonics), which causes a distorted voltage drop across the reactance of the generator. Since VFDs are nonlinear, you must include an additional generator capacity sizing factor to keep voltage distortion to a reasonable level of approximately 15% total harmonic distortion (THD) or less. The larger the generator, the greater the reduction in impedance of the power source (generator), which in turn, reduces the effects caused by harmonic current distortion.
For six-pulse VFDs, a typical generator sizing factor would be twice the running kW of the drive. This offsets any reduction in starting kW and kVA. If it is the pulse width modulated (PWM) type (or includes an input filter to limit current distortion to less than 10%), then you can reduce the sizing factor down to 1.4 times the running kW of the drive.

http://ecmweb.com/basics/sizing-gen-sets-large-motor-starting


Hope the copy & paste is Ok, I Knew VFD's would kill non-inveter rated motors at reduced speeds, Didn't know about the sizing part,

 

[Krc002]

Good call on the VFDs. i have been using them on several pieces of equipment in the shop for reducing start up current on a smaller 12.5kw set, and they work very well. they are a bit expensive in my mind though for this task, even a used one would be close to about a 1000 bucks and on top of that 30kw worth of load from the 40hp motor, i need to run the 10hp air compressor, and a 15hp dust collector, so im right at about a happy place for 60kw i imagine. A vfd for the wide belt was considered pretty seriously though, its the "accessory's" that bump me over to needing another or a secondary set when i am using the sander at closer to full capacity.

 

[1800 Diesel]

You and me both! Have a job in Lousiana in a month or two for two mep-007B's at a seafood place on the intercoastal.

Did you get 'em? Send me a pm when you get a chance...