Lights flicker on gen power

[wirebender]

What would cause lights to flicker on generator power?



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[iceworm]

I don't know if you are dealing with a 10MW or a 5kw cord and plug. So, the first answer is the generator voltage is flickering (you likely already knew that)

Here are some reasons:
Generators are not as stiff a source as a utility.
Large load swings can cause voltage drops
Motor starting
even large power tools on small generation

Now is when you give us some context so we know why you are asking.

ice

 

[qcroanoke]

What would cause lights to flicker on generator power?



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Put a good load on it and see what it does. Gensets don't like running unloaded.

 

[suemarkp]

What kind of lights are they? I had a terrible problem with my X-10 controlled lights on my generator. Some would continually dim and ramp back up, others just flickered fast. Turning them off was difficult.

The same X-10 switches would not completely turn off the lights if I had all compact fluorescents in the fixture (they'd flicker dimly when turn "off"). I had to put an incandescent in one of the fixtures on the circuit to make it behave on utility power. Perhaps it was the same issue on the generator, and just magnified.

 

[wirebender]

I don't know if you are dealing with a 10MW or a 5kw cord and plug. So, the first answer is the generator voltage is flickering (you likely already knew that)

Here are some reasons:
Generators are not as stiff a source as a utility.
Large load swings can cause voltage drops
Motor starting
even large power tools on small generation

Now is when you give us some context so we know why you are asking.

ice

I wasn't there, boss called and asked me what could be causing the lights to flicker.
If I remember correctly it's around a 35KW generator we set to be cord connected.
This was the first start up test run.
They were apparently flickering no matter what other loads were coming on. Building was not in use.
They started the genset then brought the loads on individually. Heat pumps last. Flickering throughout.

Put a good load on it and see what it does. Gensets don't like running unloaded.

They kept flickering when they brought the heat pumps in. He did say they never saw over 50 amps of load.

What kind of lights are they? I had a terrible problem with my X-10 controlled lights on my generator. Some would continually dim and ramp back up, others just flickered fast. Turning them off was difficult.

The same X-10 switches would not completely turn off the lights if I had all compact fluorescents in the fixture (they'd flicker dimly when turn "off"). I had to put an incandescent in one of the fixtures on the circuit to make it behave on utility power. Perhaps it was the same issue on the generator, and just magnified.

Incandescent and electronic T8s.
Normal switching.

 

[Sahib]

Neutral of your generator is not properly connected i.e there is loose connection in it. Check it up and tighten it.

 

[ATSman]

Faulty voltage regulator?

 

[GoldDigger]

What kind of lights are they? I had a terrible problem with my X-10 controlled lights on my generator. Some would continually dim and ramp back up, others just flickered fast. Turning them off was difficult.

The same X-10 switches would not completely turn off the lights if I had all compact fluorescents in the fixture (they'd flicker dimly when turn "off"). I had to put an incandescent in one of the fixtures on the circuit to make it behave on utility power. Perhaps it was the same issue on the generator, and just magnified.

Any two wire device, whether switch or dimmer, which depends on current through the (turned off) load for its operating power can flicker if the load is not resistive. A fluorescent with a magnetic ballast (very early CFLs?) would probably be OK, but one with an electronic ballast would flicker.

To be assured of proper operation with any kind of load (within its rating) you will need a switch or dimmer that has a separate third wire connection to a neutral for its own power. Or in some cases, again older equipment, using the EGC as a control power return conductor.

The X-10 dimmers and switches for lamps are designed so that turning the switch at the lamp off and on with the right timing can override the remote control. This is because the device can sense an interruption in the load path because it is using it for its own power supply.

The generator might also be producing noise spikes on the power line that accidentally simulate the X-10 control pulses. If that is the problem, an output filter at the generator might help. (Particularly if the generator is one with a commutator or other arc producing components.)

From what little we know second hand, this is unlikely to be the OPs problem, and it may not even be anywhere on the list of possibilities.


Motor loads with rotational inertial might not visibly show power glitches resulting from poor regulation or flaky connections, but non-incandescent lights would.

 

[wirebender]

I haven't been out to check this, yet.

If and when I do, I'll let y'all know what i find, thanks for the suggestions.

 

[Shanky]

Shanky

Shanky

I haven't been out to check this, yet.

If and when I do, I'll let y'all know what i find, thanks for the suggestions.

May want to check out the stability adjustment on the voltage regulator, this can be done easily in the field by plugging in a drop cord light with a standard light bulb, and you will see the pulsation, adjust till it just becomes constant.