VFD, Active Harmonic Filter, Power Consumption???

[Valvecrazy]

Looking at this link;

http://ecatalog.squared.com/pubs/Po...rection Equipment/Accusine PCS/5820BR0701.pdf

What is 1800-2150 Watts of heat loss per 50A??

 

[dpc]

What page are you looking at?

 

[Valvecrazy]

Product Specification page 7.

 

[ScottyUK]

A 50A rated unit in a NEMA 1 housing operating at rated current will dissipate 1800W of losses as heat.

A 50A rated type in a NEMA 12 housing operating at rated current will dissipate 2150W of losses as heat.


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If we learn from our mistakes I'm getting a great education!

 

[Valvecrazy]

I can read that much. Doesn't that mean I am using from 7% to 9% more energy?

 

[jraef]

No, it means that of the energy going in, that much is being lost as heat.

By the way, measure the heat loss across a restricted valve. Most of it is carries away in the fluid, but that energy is still lost, and it has to come from somewhere.

 

[Valvecrazy]

"No, it means that of the energy going in, that much is being lost as heat."

So to control the harmonics from a 50 amp motor, the active harmonic filter is losing 2150 watts to heat. Isn't that adding another 2.88 HP load to the system?

 

[jraef]

Yes, well sort of...

IF you have decided that harmonic mitigation is important to you and have decided to use a device such as that, then of the 50A going through it, up to 2150W of that energy will be lost as heat.

BUT (and this is a BIG BUT ) a 50A Active Filter is not used for a 50A motor, the 50A refers to handling 50A of harmonic current, not 50A of load current. 50a of harmonic current would imply a much much bigger motor; probably in the range of 300-400HP (assuming 460V). So that "2.88HP" of losses becomes somewhat insignificant compared to the potential energy savings of using a VFD compared to throttling. As I said, think about the energy loss across a valve on a 350HP pump. Probably more than that, and all that energy had to come from the pump motor. I'm not an ME, but I'd bet it is a wash at best...

http://www1.eere.energy.gov/industry/bestpractices/pdfs/control_valves_pumping_ts10.pdf