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Discussion Starter · #1 ·
As some of you know, I am putting two leaf motors and , currently, two volt packs on my truck. I am in the process of designing the cooling system (not cabin heat) but I cannot find a typical coolant flow rate needed to keep the smoke inside the inverter. I don't have a heat pump or compressor so I will just be pumping it to the rad under the truck. For the life of me, I can't find anything indicating a minimum flow and/or dT needed through the inverter and motor. Can anyone help me?
 

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I did some digging in the 2014 service manual and online but was unable to find anything that mentioned flow rate. I don't have anything hooked up right now so I can't even go out and give you estimate. Sorry.

Bill
 

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Discussion Starter · #3 ·
Well, barring any information, I could work backward using the rough efficiency of the motor/inverter combo and the gross kw input and approximate something but I think it would be a best guesstimate. Would assuming a 90% overall efficiency be too bold?
 

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Well, barring any information, I could work backward using the rough efficiency of the motor/inverter combo and the gross kw input and approximate something but I think it would be a best guesstimate. Would assuming a 90% overall efficiency be too bold?
Efficiency of the motor and inverter will be lower than that at less-than-optimal conditions, but that's only a concern at high power. The worst extremes at full power in the maps in a 2013 DOE report are
  • at about 3,000 RPM and full load, motor 94% and inverter 96% for 90% overall (and 8 kW of heat production)
  • at 10,000 RPM and full load, motor 95% and inverter 99% for about 95% overall (and 4 kW of heat production)

As speed drops below 3,000 RPM efficiency gets much worse but power drops off by roughly the same amount, so the heat dissipation rate is similar.

So, I think the assumption of 90% or better efficiency at up to 80 kW (per drive unit), for a heat load of up to 8 kW (per drive unit) is reasonable.
 
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