Generator unbalanced load


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Old 08-15-22, 01:30 PM
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Generator unbalanced load

I want to use a 5.5kw genset wired for 240/120 with its two windings in series for a single heavy 120v load, so using only one winding. If the load is less than 2.5kW, is the genset happy?
 
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Old 08-15-22, 02:44 PM
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You don't say how much less so I will assume 2.5 kW. 2.5kW is 20.8 amps at 120 vac. If the generator provides a 120 vac connection that is rated for 20.8 amp or more you are OK. Otherwise you are limited to the 120 vac connection rating. The connecting cable must have at least the same current rating as the load current.
 
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Old 08-15-22, 03:25 PM
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What i am worried about is vibration when one winding has all the load, and the other winding has no load.
 
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Old 08-15-22, 04:06 PM
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It won't be a problem. The windings are dispersed evenly around the generator.
 
telecom guy voted this post useful.
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Old 08-15-22, 06:29 PM
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with its two windings in series for a single heavy 120v load,
You mean in parallel. Two 120v windings can't deliver 120v in series.

The two 120v windings are not in phase and could not be paralleled.
 
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Old 08-16-22, 03:49 AM
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I doubt the telecom guy is thinking about changing the internal wiring of the generator.
 
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Old 08-16-22, 04:10 PM
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I toured the actual generator factory yesterday; these are small (< 10kW)marine diesel gensets.
There are two windings, parallel or series wired. In parallel, 120V at 42 Amps or 240/120 at 5.5kW max; as one example I want to consider buying.
The wiring makes sense, since you need the 120V windings in phase to provide 240 when series; and, in parallel, they offer 2x the current from one winding set, with the Volts NOT additive. I viewed the 4 posts brought out to put jumpers on.

Anyway, the vendor was not thrilled with loading only one winding heavily, but then, he wasn't an engineer, and I'm not sure of what led him to this "belief".
 
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Old 08-16-22, 04:16 PM
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You mean in parallel. Two 120v windings can't deliver 120v in series.

The two 120v windings are not in phase and could not be paralleled.
Nope, sometimes I want only 120V at high loads, taking only one of the phases out. I believe the two windings ARE in phase. Only way to get 240 when they stack in series, right?
 
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Old 08-16-22, 05:17 PM
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Are the 4 terminals you mentioned in post 7 available to the owner to connect the 2 generator windings to each other and the load? If so, what info is provided to insure polarity is maintained when connecting in series or parallel to obtain the correct voltages?
 
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Old 08-16-22, 05:24 PM
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Are the 4 terminals you mentioned in post 7 available to the owner to connect the 2 generator windings to each other and the load? If so, what info is provided to insure polarity is maintained when connecting in series or parallel to obtain the correct voltages?
Color coded wires, and the wiring manual. Most owners don't get in this deep, I'll bet.
 
 

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