Tek-Tips is the largest IT community on the Internet today!

Members share and learn making Tek-Tips Forums the best source of peer-reviewed technical information on the Internet!

  • Congratulations TugboatEng on being selected by the Eng-Tips community for having the most helpful posts in the forums last week. Way to Go!

Motor Supply Voltage and Performance

Status
Not open for further replies.

ProfT

Electrical
Joined
Mar 22, 2011
Messages
7
Hi peepz, just a quick one. What is the difference in performance between a 250 kw, 525V motor and a 250 kw, 6600V motor?

Thanks.
 
Not much. No point in using a 6 kV motor if you have a 525 V grid. If you don't - then an MV motor may make sense. But usually, they need to be quite a bit larger to motivate the more expensive cables and switchgear.

Gunnar Englund
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.
 
One issue on the side of MV, if you have 6600V available already, but you have to buy a transformer to get 525V (or 575V?), then there will be losses in the transformer to consider for overall throughput efficiency compared to running at 6600V. The cost of those losses, compared to the added capital equipment cost of the 6600V equipment as Skogsgura pointed out, would need to be evaluated.

But from a motor standpoint, kW is kW is kW, no difference in performance.


"Will work for salami"
 
Also consider cost of labor since qualifications for working at 6.6 kV vs 0.525 kV is different in some jurisdictions.
 
If you would intend to start the motor D.O.L. [direct-on-line] you could encounter a large starting current, which in turn could produce a very large voltage drop and disturb the other motor already functioning. However, usually 250 hp is still possible.
By the way, since copper is the more valuable than insulation, the medium voltage cable could be cheaper.
 
Status
Not open for further replies.

Part and Inventory Search

Sponsor

Back
Top