PTO Generator - how do they work?

[Jay4200]

How does a PTO generator regulate voltage and frequency? Do you just set the tractor RPM to some specified number, and hope that your tach is accurate? Frequency is surely a brute-force function of RPM, but is there any kind of secondary voltage regulation, or is that also at the mercy of your speed lever setting?

JayC

 

[JB4310]

You do have to get it close with the tach/ engine speed.

Most modern pto gennys have some type of meter or light system to keep you within spec.

Most modern pto gennys over 10 kw have automatic voltage regulation, AVR.

The older or smaller units used capacitors.

But neither of those regulation systems is foolproof you do have to be pretty close with the input rpms.

Most of the time that will require manual throttle input adjustment from no load to full load on the generator. That's from my experience with a 10 KW capacitor regulated pto generator. Some have said they were able to set throttle and forget it with an AVR unit.

JB

 

[Mickey_Fx]

Voltage is self regulation and as you suggest, freq is a function of rpm. You should at least check freq the first few times you use the genny so you can see what the tach is reading when proper freq is reached.

A pto genny is at the mercy of the tractor's gov to control engine/pto rpm. Some tractor's do better than others. Again, use of freq counter is needed to see how well the gov controls engine speed. IMO you should set the rpm so freq is right on when a mid level of power is being produced. After set, see how much the speed varies when load is either increased or decreased. I'd not be too pleased if freq changes more than +/- 2rpm over the load range.

 

[psdx]

One thing to consider about the tractor's ability to keep the rpm steady to hold the frequency... If the tractor is producing 90% of the possible current output, due to the PTO max hp - you may see some fluctuations with load changes. The general rule of thumb is 2 hp for every kilowatt. So if you have 20hp at the PTO and your load is 9kW, then load fluctuations will take the governor a quick second to adjust. But on the other had if you were pulling this same 9kW on a tractor that had 40 hp at the PTO, the load changes would be much less noticeable.

I'm just pulling numbers out of the air to illustrate, but the bottom line is - just like anything else, if you have a little more hp than you need to meet the specs, you are less likely to see output frequency fluctuations as the load changes (like starting a well pump or big air compressor).

 

[Car Doc]

My old winco has one meter with a green area at 260v set the throttle at that green area and thats it.

 

[Willl]

My old winco has one meter with a green area at 260v set the throttle at that green area and thats it.

How close is that to a 540 RPM PTO output ?

 

[nybirdman]

Just had to use my 10K Pto gen last wk.It is a TigerPower...2008 model,have used it three times total maybe 25 hrs.It has a volt meter and duty cycle.
120 volts at 60 HZ is where it needs to be(for the U.S)
My tractor is 44HP...I just set the PTO at about 520RPM's...gets the gen where it needs to be.I run my whole house and detached garage with no problems.I never noticed the tractor loading up...seemed to run at a steady speed.

 

[randyhoekstra]

I have a katolite 15kw pto generator. as pto is running i have NO voltage on the hot side of the breaker what do i check?

 

[alco141]

wow,
you may have a generator that lost its magnetism and will need a current applied to the breaker to remagnitize the field, you could have some bad diodes, or broken or mice chewed wires, burned fields, there are a whole bunch of reasons why this does not work, you could have a bad breaker. lots of items to think about, start with the owners manual and it will usually tell you what to check first.

 

[Car Doc]

I second the rodent damage being a possible issue. There isn't much to go wrong just from sitting unless its exposed to the weather. Most of us keep at least that piece of equipment inside if we can or covered up well.