Comments for Power Quality Advisors Blog

Comment on by Tom Flaugher

Tom Flaugher — Tue, 15 May 2012 15:16:01 +0000

Why don’t endusers get the rated service life from batteries ?

http://genesysm2m.com/documents/LifeExpectancy32812rev4.pdf

Comment on by Power Quality Advisor

Power Quality Advisor — Thu, 21 Jul 2011 15:10:47 +0000

I would thrilled to do both a west coast and east coast version. My thinking is that we work together to solicit the type of assistance we need for this.
Excellent idea!!!!

Comment on by Geoffrey Lacefield

Geoffrey Lacefield — Thu, 21 Jul 2011 14:35:32 +0000

Is there going to be a Battery Conferance on the west coast? Batt con is heald on the east coast every year. Isn’t there a high enough demand for this type of conferance on the west coast as well?

Comment on About Power Quality Advisors Blog Site by Julius Dumapit

Julius Dumapit — Mon, 13 Jun 2011 19:06:03 +0000

What are the requirements for battery rooms for both VRLA and wet batteries? I am trying to determine if I will classify a battery room for (2) 60 cell VRLA batteries, a Class 1 Div 2 hazardous environment. We designed the room to have a redundant Air Conditioning System, and also exhaust fans.

Comment on About Power Quality Advisors Blog Site by Joseph DiSalvo

Joseph DiSalvo — Tue, 24 May 2011 13:59:21 +0000

Thanks from Mitsubishi!

Hi Art, It was great to see again, as usual! We appreciate you taking the time out of your busy schedule to meet with our team. The presentation was very informative and a good learning experience for all. Also, meeting with our buyers and engineers the day before to review our spec was very helpful. Again, thanks very much for all your expertise and we hope to be doing business with you in the near future.

Regards,
Joseph DiSalvo
Global Sourcing Specialist
Mitsubishi Power Systems Americas, Inc.

Comment on by Jim McDowall

Jim McDowall — Fri, 25 Mar 2011 17:57:27 +0000

Lead-acid batteries, whether vented or VRLA, can generally be recharged after a discharge using the float voltage. Equalizing may used with vented batteries for addressing voltage imbalances between cells (although such imbalances are normally harmless), to reduce acid stratification (although to be effective this requires that the cells produce sufficient gas to help mix the electrolyte), and for faster completion of recharge. This last point is more of a challenge with vented batteries because the negative becomes polarized at 80% to 90% state of charge, causing the charge current to be greatly reduced. With VRLA batteries the negative is depolarized by the internal recombination process so the charge is closer to completion by the time the current tapers down. The reduction in negative plate polarization also tends to reduce cell-to-cell voltage variations (once the cells have all become fully recombinant), and of course there is no acid stratification issue with VRLA.

Comment on by Julius Dumapit

Julius Dumapit — Wed, 23 Mar 2011 18:26:21 +0000

Explain why a VRLA type of batteries don’t need to be equalized?

Comment on by Larry Meisner

Larry Meisner — Fri, 07 Jan 2011 21:39:14 +0000

You are refering to vented nickel cadmium battery systems if you are talking about “prolonged float charge” vs “constant current” charge data. If you are comparing product manufacture’s you should always compare the data based on the same charging characteristics. Nickel cadmium batteries like to be charged with constant current and retain their highest voltage level on discharge when charged constant current. However, the industry uses constant potential charging, usually a boost charge at a higher voltage and followed by a float voltage charge at a lower voltage level. To keep the answer simple, when nickel cadmium batteries are charged constant potential and then floated over a period of time, on discharge the discharge voltage curve is depressed, resulting in the battery reaching it’s end voltage sooner. This does not mean it does not have capacity, only at a lower voltage. So from a practical standpoint, you should always use the “prolonged float” voltage information to size your nickel cadmium battery system. This will guarantee it performes to your load profile requirements.

Comment on About Power Quality Advisors Blog Site by W Bennett

W Bennett — Mon, 03 Jan 2011 16:29:59 +0000

Regarding transformer insulation systems:
* UL classifies insulation systems by operating temperature; each system has a letter designation (A, B, etc.). Higher letters equal higher temperatures; lower letters = lower temperatures = higher cost. We usually now refer to the higher grades as “Class 200″ or “Class 220,” rather than the letter designations N and R, respectively.
* OEM manufacturers like the higher temperature grades because they reduce component costs. In a competitive environment the savings are passed on to the customer. In general, you shouldn’t try to specify to a supplier what specific insulation system should be used, but it’s OK to specify that the transformer use a UL Recognized system. Transformers last for decades, even operating at higher temperatures.
* Some users specify that transformers use copper conductors instead of aluminum. A properly designed and constructed aluminum coil (using TIG welding) is as reliable as a copper coil.
* To answer Mr. Cabrera’s specific question, a class F transformer is rated for 155°C. When a safety rating agency evaluates a product, they will ensure that the maximum temperature rise of the transformer under worst-case conditions will keep the insulation below that number. An agency certification is the really important spec.

Comment on About Power Quality Advisors Blog Site by Jose Antonio Cabrera

Jose Antonio Cabrera — Thu, 23 Dec 2010 03:01:14 +0000

Question reganding SCR chargers. What does a utility charger(25 to 200A output) specification should state about the isolating transformer specification/ratings? For example, a manufacturer stated that their transformer has Class F insulation.