Question about surging when dryer turned off.

[Rail Dawg]

Model 5242 Guardian 13,000 watt. 3 bedroom house.

When I turn on my 240 volt AC Dryer the generator keeps running no problem. However when I turn the dryer off the generator surges a bit and the lights in the house go dim. The generator then quickly gets back up to steam and the house is powered normally.

Is it OK to see this kind of surge? I turned on all the lights in the house and ran the dryer and microwave to load up the generator as much as possible and it does fine.

Thanks for any inputs.

Chuck

[mike_y]

Model 5242 Guardian 13,000 watt. 3 bedroom house.

When I turn on my 240 volt AC Dryer the generator keeps running no problem. However when I turn the dryer off the generator surges a bit and the lights in the house go dim. The generator then quickly gets back up to steam and the house is powered normally.

Is it OK to see this kind of surge? I turned on all the lights in the house and ran the dryer and microwave to load up the generator as much as possible and it does fine.

Thanks for any inputs.

Chuck

I have seen exactly this effect in a 16/18 KW 5416. There are 2 feedback loops: a voltage regulator which adjusts the rotor field and a speed controller which adjusts the gas flow to the engine. The first is electrical and the second is in part mechanical and my guess is that they don't respond equally fast to sudden changes in load so there may be brief voltage and frequency fluctuations but they get their act together pretty quickly.

[Rail Dawg]

I have seen exactly this effect in a 16/18 KW 5416. There are 2 feedback loops: a voltage regulator which adjusts the rotor field and a speed controller which adjusts the gas flow to the engine. The first is electrical and the second is in part mechanical and my guess is that they don't respond equally fast to sudden changes in load so there may be brief voltage and frequency fluctuations but they get their act together pretty quickly.


That makes sense. Thanks Mike!

Chuck

[Gman1]

Keep that up and you can kiss your rotor goodbye. Your machine shouldn't be running a dryer. I am guessing that your dryer is about 30 amps at 240 and your microwave is about 15 amps at 120, plus whatever lighting load you had. When you run all of those together you have approached or exceeded the full capacity of one leg (the one with the micro on it) and it will let you down if you do that for long. I know it will do it, but it doesn't mean you should. When everything went dim, everything was running on low voltage...really bad for your electronics. I have replaced a few rotors and the common denominator seems to be running the generator beyond its limits.

[Rail Dawg]

Keep that up and you can kiss your rotor goodbye. Your machine shouldn't be running a dryer. I am guessing that your dryer is about 30 amps at 240 and your microwave is about 15 amps at 120, plus whatever lighting load you had. When you run all of those together you have approached or exceeded the full capacity of one leg (the one with the micro on it) and it will let you down if you do that for long. I know it will do it, but it doesn't mean you should. When everything went dim, everything was running on low voltage...really bad for your electronics. I have replaced a few rotors and the common denominator seems to be running the generator beyond its limits.


I see your point about too much on one leg. I had not thought of that.

What if during an extended power outage and we need the dryer we power down the high-load items and just run the dryer? It seems like the generator would be just fine running that load?

I appreciate the help. I knew the A/C wouldn't be doable but this is the first time I've been told not to run the dryer.

Thanks!

[pcfrisch]

What is the power rating on the dryer?
You can also balance the load. Does the generator connect directly to your circuit breaker box

[Rail Dawg]

What is the power rating on the dryer?
You can also balance the load. Does the generator connect directly to your circuit breaker box


It's 240 volts at 26 amps. The generator (5242 13kw) is wired into the ATS supplied by Generac.

It only surges significantly when under full load and dryer is turned off. If there is just the dryer on the generator it surges just a little bit when the dryer is turned off.

Again the help is appreciated.

[mike_y]

Keep that up and you can kiss your rotor goodbye. Your machine shouldn't be running a dryer. I am guessing that your dryer is about 30 amps at 240 and your microwave is about 15 amps at 120, plus whatever lighting load you had. When you run all of those together you have approached or exceeded the full capacity of one leg (the one with the micro on it) and it will let you down if you do that for long. I know it will do it, but it doesn't mean you should. When everything went dim, everything was running on low voltage...really bad for your electronics. I have replaced a few rotors and the common denominator seems to be running the generator beyond its limits.

Quite correct. You don't want to run any machine for extended periods close to its rated capacity; that's for occasional bursts of demand, like a car accelerating onto a freeway. Rail Dawg's 13K generator is rated at 54 A, and if the drier is 30 and the microwave 15, yes, it is approaching capacity on one leg. But the low voltage incidents he and I referred to were momentary dips lasting maybe half a second; most electronic equipment can cope with that, if it doesn't happen too often. If it does, then a line interactive UPS could be of value on critical devices, and would also get them through the brief blackout on a utility failure startup. Actually, in computers and the like, the 120 V never gets beyond the power supply module; the electronics runs on low voltage DC lines, 5 and 12 VDC for example, which are presumably well regulated by the switching power supply.