Zing
Well-Known Member
I'm confused by this. The Frigomar brochure linked to by Portofino talks only about using a psm motor, a 3 phase motor therefore in all probability and no different from the Cruisair you mention. There is no mention of DC. However, I found their smaller stand alone units are described as being DC inverter powered motors. This doesn't sound correct to me as inverter drive means Variable frequency drive and this means AC frequency. There is no such thing as DC frequency. Introduce a frequency and you have AC. You can have pulse control, but that is not AC either. Or it could really be DC, but the what would be the point of an inverter then? I suspect there is marketing muddle at play.Of course it does. Why wouldn't it - that would be totally pointless.
Portofino, I know you love your airco but you have been bamboozled if you believe your smart inverter-fed DC compressor motor is better than the smart inverter fed 3ph AC motors that I and Nigel have. They just are not. There are some operating modes at which DC brushless are marginally better than smart-inverter induction motors and some where the opposite is true, but it is absolutely untrue to say DC brushless are generally better than smart-inverter induction motors. Indeed in high performance applications the induction motor is invariably better. You can insist on saying the opposite just cause your airco tech said so, but I doubt he really understands electric motors properly, really properly.
Veco also do a small VFD unit to compete with Frigomar and both can operate to about 20% of nominal output, with no start up peaks, plus a very high level of COP efficiency. Very attractive units and better than anything I have seen in the Cruisair lineup.
I don't think it is relevant to the units as mentioned, but I do think brushless DC can be extremely efficient actually, no less so than 3ph VFD motors.
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