PTO Generator inadequate for larger HP motors?

[arcteryx]

The PTO generators I a looking have have a THD of less than 5%, the IMD with AVR is <1%, this is from IMD when I spoke to them. It seems the ones under 15/16KW have lower THD than the larger ones, at least the ones I have looked at. Point is, I am good with that and the electronics should be fine with that distortion

 

[Topzide]

Might want to check out Central Georgia Generators. Just Google them for web site. They have pto kits for good prices. I'm thinking of getting one through them.

 

[aircommuter]

Bad information from you (as usual).. If the generator has a gas engine, then it will be 2 pole. If it's diesel powered, then 4 pole because diesel engines don't make enough rpm to produce 60 hertz.

Ie: 60 Hz at 3600 rpm (gas)
60 Hz at 1800 rpm (diesel)

My Generac is 4 pole, diesel powered.

I have propane powered generator which is a gas engine, 460 Ford to be exact and the it is three phase with 6 poles, reconnect-able. Of course it runs 1800.

 

[aircommuter]

Maybe a VFD is in your future.

 

[NoSmoke]

I don't understand why their TX12 can't start a 3 hp motor. 12,000 watts is about 5 times the running wattage of your 3 HP motor. But what really matters is the current draw when starting. Depending on the motor and the mechanical load on the motor when it starts the starting current can be more, much more, than 5 times the running current. I think Baumalight is just trying to cover their butt because they don't know what the starting current of your motor is going to be.
Anyway, if you have already bought the generator all is not lost. Furthermore, if you haven't bought it but really want it or something similar you can still do so. What you need is a soft starter. Even though you can build one yourself I have a sneaking suspicion that you would rather not. So, for your size of motor, a soft starter can be had for less than 150 frog pelts, AKA greenbacks. For example check out this link: ATS01N112FT | Altistart 01 Soft Start (ATS01), for Asynchronous Motor, 12A, 110-480V, 1.5-7.5 HP, 1.5-5.5 kW, Single-phase, Integrated Bypass, w/Heat Sink Pack of 1 | Square D by Schneider Electric . $136.90 for a soft starter that can handle your 3 HP well pump while at the same time protecting your Baumalight generator. Of course you should ask Baumalight if using a soft starter is OK but it should be. After all what really matters is what the load is that the generator sees.
Cheers,
Eric

I'm not sure that is what is needed here. Looked at the specs and it appears, at least to me, that the 7.5 HP, 5.5KW is for a 3-phase application (although the specs also say it is a 1-phase starter so who knows?). Quoting the spec:

"This Altistart 01 can be used for a motor rated power up to 5.5kW or 7.5hp for 3-phase (110V to 480V AC) and up to 1.5kW for single phase (110V to 230V AC)."

I wonder how all that actually shapes up for starting a 3HP motor (unless it's a 3-phase and the device does 3-phase as well).

 

[BubbaLouie]

I was looking at Baumalight's site at the TX12 specifically, and it had a warning in the manual to not use for over 2HP motors or the generator could be damaged. I emailed Baumalight and they confirmed, none of the TX series are rated for more than 2HP regardless of watts, and they recommend the 4 pole KR or QC series. I have a 3HP well pump and need something to power it.

If Baumalight says this, do other manufacturers - Winco, Northstar, IMD, HF- have a similar requirement? I have looked at some of them but have never come across this type of warning.

For those with PTO generators, do you run motors larger than 2 HP and if so, are there any problems or issues?

The starting inrush current for an induction motor can be as high as 7 times the full load running current (FLA).

You may want to check into a soft start kit for your well pump motor, which will reduce the starting inrush current.

Yes, this is very real.

 

[NoSmoke]

An old trick to start larger electric motors is to run up a smaller (say 1hp) motor up to full speed and then switch the larger motor inline (parallel) to the running motor.
The smaller motor will actually act as a generator for a second or two assisting the generator with the surge necessary to start the larger motor.
Disconnect the "assisting" motor after the big boy starts.

My two cents worth...

That's a cool idea. Would adding a flywheel to the smaller motor enhance the generator effect?

If one where to do that, I wonder how small a gen could start a 1 1/2 HP well pump motor (which is what I have and my 3 KW generator won't, not surprisingly, start it)?

 

[Chewwy]

I have propane powered generator which is a gas engine, 460 Ford to be exact and the it is three phase with 6 poles, reconnect-able. Of course it runs 1800.

With 6 poles it has to run at 1200 rpm to generate 60 htz.

The formula is rpm = (htz x 60 x 2) / number of poles

(60 x 60 x 2) / 6 = 1,200

 

[MAX-24-Dean]

Most of the entire home generators sold today are 2 pole generators, So, that would have to be true for them too.

SR

It is for the low HP gen sets that we are talking about in this thread. Most get high demand loads (causing voltage sag) placed on them from individuals not being able to manage loads.
If you know how to manage your loads, it not as much of a problem.
I did look up to see if a PTO gen company stated thier pto gensets are for farm use and not for resdential loads.
See link below where it states this for Baumalight 2 pole PTO gensets.
Link basically says, not designed for electronic loads in households or shops.

TX Series Generators | For Barns / Jobsites | NOT Designed For Electronics In Households Or Shops - - Beaver Valley Supply

TX Series Generators | For Barns / Jobsites | NOT Designed For Electronics In Households Or Shops - - Beaver Valley Supply

beavervalleysupply.com

A good example off this is one of my neighbors has replaced there inverter refrigerator because of poor AC waveform due to voltage sag from the utility power they have. Not even voltage sag from a PTO genset.

Showed them on a recording oscilloscope what happens to thier power at peak demand on the utility vs my off grid inverter perfect sine wave.
My inverter fridge is still running strong after 15 years.
Utility has since begun adjusted thier voltage tap during high demand seasons for this feeder.

 

[MAX-24-Dean]

Bad information from you (as usual).. If the generator has a gas engine, then it will be 2 pole. If it's diesel powered, then 4 pole because diesel engines don't make enough rpm to produce 60 hertz.

Ie: 60 Hz at 3600 rpm (gas)
60 Hz at 1800 rpm (diesel)

My Generac is 4 pole, diesel powered.

mis-information is posted above, 2 pole generators don't care if they are being driven by a gasoline prime mover or a diesel prime mover or a hydraulic prime mover. neither do 4 pole or 6 pole gensets.

I like to see things corrected if thier is some bad information I inadvertantly post or because I lack knowledge and shouldn't have posted in the first place. Both have been the case for me, but I go back and correct it and reply with an update.

Most of the entire home generators sold today are 2 pole generators, So, that would have to be true for them too.

SR

I see his post as being conscientious and also took this as a statement and as a question to me. so I responded with more information.

 

[Sawyer Rob]

Bad information from you (as usual).. If the generator has a gas engine, then it will be 2 pole. If it's diesel powered, then 4 pole because diesel engines don't make enough rpm to produce 60 hertz.

Ie: 60 Hz at 3600 rpm (gas)
60 Hz at 1800 rpm (diesel)

My Generac is 4 pole, diesel powered.

 

[Sawyer Rob]

It is for the low HP gen sets that we are talking about in this thread. Most get high demand loads (causing voltage sag) placed on them from individuals not being able to manage loads.
If you know how to manage your loads, it not as much of a problem.
I did look up to see if a PTO gen company stated thier pto gensets are for farm use and not for resdential loads.
See link below where it states this for Baumalight 2 pole PTO gensets.
Link basically says, not designed for electronic loads in households or shops.

Here's what Winco says about their 15kw PTO genset,

Low Harmonic Distortion
Provides clean power for both farm and home.

W15PTO 120/240 1-PH 515 RPM | WINCO

WINCO has been building PTO generators since 1950. Our 50PTO has been redengineered with top quality components, including our in-house designed gearcase.

www.wincogen.com

I've run my whole house without any problems at all...

SR

 

[5030]

2 pole genny's must rotate at 3600 rpm 4 pole 1800 rpm.

Plain and simple.

Diesels don't turn at 3600 rpm that I know of, gas motors do.

My diesel standby is governed to 1800 rpm.

Not complex at all.

 

[ptsg]

Interesting. My 10kW Leroy Somer 2 pole 3 phase generator spins at 3000 RPM for 50Hz and it's powered by a 25HP Slanzi DVA1030 Air cooled diesel engine that spins at 2500 RPM.

The diesel engine doesn't necessarily needs to spin at the same speed the generator needs to spin.

 

[aircommuter]

With 6 poles it has to run at 1200 rpm to generate 60 htz.

The formula is rpm = (htz x 60 x 2) / number of poles

(60 x 60 x 2) / 6 = 1,200

Read for yourself. Kohler 48RCLC-QS3 48RCLC - 50kW Emergency Standby Power Generator 120/240V Three-Phase

 

[MAX-24-Dean]

2 pole genny's must rotate at 3600 rpm 4 pole 1800 rpm.

Plain and simple.

Diesels don't turn at 3600 rpm that I know of, gas motors do.

My diesel standby is governed to 1800 rpm.

Not complex at all.

Kubota and Yanmar both make diesel engines designed to run at 3600 rpm for use in driving small 2 pole generators for 60 hertz power.
Most diesel gensets are 4 pole generator heads with diesel prime movers running at 1800 rpm for the north american market.

 

[grsthegreat]

Bad information from you (as usual).. If the generator has a gas engine, then it will be 2 pole. If it's diesel powered, then 4 pole because diesel engines don't make enough rpm to produce 60 hertz.

Ie: 60 Hz at 3600 rpm (gas)
60 Hz at 1800 rpm (diesel)

My Generac is 4 pole, diesel powered.

absolute nonsense. i take care of many gas 4 pole generators. both propane and nat gas.

 

[Chewwy]

Read for yourself. Kohler 48RCLC-QS3 48RCLC - 50kW Emergency Standby Power Generator 120/240V Three-Phase

Unclear what your point is. This machine is NOT 6 pole. This machine is 4 pole, 1,800 rpm.

 

[Chewwy]

Interesting. My 10kW Leroy Somer 2 pole 3 phase generator spins at 3000 RPM for 50Hz and it's powered by a 25HP Slanzi DVA1030 Air cooled diesel engine that spins at 2500 RPM.

The diesel engine doesn't necessarily needs to spin at the same speed the generator needs to spin.

Your 2 pole genny MUST spin at 3000 rpm to produce 50 htz.
Your prime mover can of course be geared to operate at a different speed.

 

[ptsg]

Your 2 pole genny MUST spin at 3000 rpm to produce 50 htz.
Your prime mover can of course be geared to operate at a different speed.

Of course it can. That's the entire point. The guy was claiming that only gas engines would run 2 pole generator heads, which is obviously false. Not only they can speed up the diesel engine RPM via gears or pulleys and belts, they also make plenty of diesel engines that can work at 3000/3600 RPM all day long, they're just noisier for the most part.

Mine is belt driven and since I don't actually need the 10kW, I got a bigger pulley for the engine and I'm now running the engine at around 1800 RPM. Plenty of power for a 3HP well pump and one of those small 50 liter air compressor. Way less noise and fuel consumption this way.