[ARC5] No-load current of dynamotors?

[J Mcvey]

 Does that inverter use germanium transistors by any chance?

    On Friday, March 11, 2022, 09:21:15 PM EST, Charles via ARC5 <arc5 at mailman.qth.net> wrote:  
 
 Just wondering if anyone has measurements on the no-load input current 
of their dynamotors (of various sizes).

My Bendix 2 KVA aircraft inverter is rated at 115 amp full-load draw, 
per the nameplate. Now that I have a monster unregulated 24-28 volt 
supply, I have measured the idling current at 26V at 40 amps. 1/3 of the 
full-load current seems kind of high? I was expecting more like 10-20%.

The only 120 volt resistive load I had on hand was a 525 watt heat gun 
element, and the output voltage dropped only a few tenths of a volt, 
while the input current rose to 75 amps. Next data point will be a 900 
watt electric heater (the inverter is rated for 1 KVA single-phase), 
unless I rig up a three-phase load.

(The only other dynamotors I have are small ones for "ARC-5" receivers 
and I haven't checked them yet).

It does have two carbon-pile regulators, the original selenium 
rectifiers, and a couple of relays that draw a little here and there, 
but nothing's getting significantly warm except the air coming out of 
the rotating assembly (it has fans on each end cap that draw in, and 
exhausts from the middle). I can only assume that this is normal 
behavior? Thoughts?

Cross-posted to Boatanchors and ARC-5 lists.


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