PTO Generator inadequate for larger HP motors?

[etpm]

Just to add an option, I *think* you could make this work by getting other motors and adding them to the circuit, starting them one at a time. Even better if you add the right amount of capacitance across those motor's terminals to counter their inductance -- this is the amount of capacitance that minimizes the current draw when the motor is running at full speed with no load.
These motors will all act as flywheels to create the extra wattage it takes to start your large motor. The power grid has the same property, and this is where very short term power reserves come from (for example to handle an extra load for a second, which is way too brief to add generator capacity).

There are multiple DIY schemes to ameliorate the high motor starting current problem but I have the feeling that the OP is not interested in a DIY solution.
When I first started my machine shop in my garage over 40 years ago I had to make my own 3 phase. I bought a "Phase Converter" that was basically just a couple capacitors and a relay. A trip to a good library helped me learn about rotary phase converters and also how adding running motors could help with subsequent motor starting loads. And I used this information. But it was 40 some years ago.
It's good that you posted about this. Perhaps you could post some links or instructions on how to do this for the OP's motor load just in case the OP is interested in trying a DIY solution.
Eric

 

[hiddentacocatneddih]

Buy a pto pump and run the pump directly?

 

[LouNY]

There are multiple DIY schemes to ameliorate the high motor starting current problem but I have the feeling that the OP is not interested in a DIY solution.
When I first started my machine shop in my garage over 40 years ago I had to make my own 3 phase. I bought a "Phase Converter" that was basically just a couple capacitors and a relay. A trip to a good library helped me learn about rotary phase converters and also how adding running motors could help with subsequent motor starting loads. And I used this information. But it was 40 some years ago.
It's good that you posted about this. Perhaps you could post some links or instructions on how to do this for the OP's motor load just in case the OP is interested in trying a DIY solution.
Eric

Or, just get a slightly larger 4 pole generator.

 

[Sawyer Rob]

Or, just get a slightly larger 4 pole generator.

My 15kw Winco would start it, no problem at all, a 3hp motor is no big deal...

I've exercised my Winco by powering my shop many times, and that means starting motors in the shop, it works perfectly.

SR

 

[LouNY]

My 15kw Winco would start it, no problem at all, a 3hp motor is no big deal...

I've exercised my Winco by powering my shop many times, and that means starting motors in the shop, it works perfectly.

SR

The OP was concerned as the pto generator that he was looking a 12Kw had a warning not for starting a 3hp motor. That was a 2 pole generator. A four pole should not have any problem.

 

[Sawyer Rob]

The OP was concerned as the pto generator that he was looking a 12Kw had a warning not for starting a 3hp motor. That was a 2 pole generator. A four pole should not have any problem.

I agree, but I'm just saying that maybe a *brand switch* would be a good option for him too.

BTW, my Winco is a 2 pole also...

SR

 

[Chewwy]

Thank you for the replies. I have not bought one yet, but I’m getting very close to pulling the trigger. I like the Baumalight, but the warning may be a dealbreaker.

Here is what the response was from them, it could be a CYA statement or some deep electrical reason as mentioned above.

”The info is indeed correct & the TX series is a 2 pole unit & is not capable of handling the start up requirements of motors beyond 2 Horsepower. The KR or QC series are 4 pole winding units delivering a more consistent supply & are capable of handling such high start loads of larger motors”.

Looking at the 10KW and 16KW IMD, they’re on sale for the next week. I really like the AVR, although a Sense Flex or similar could do they same. However they don’t have surge ratings, just continuous.

I am also considering the 12k Northstar, it gets good reviews, with surge to 13kw. And the 15KW Winco.

On a slightly different question, for those with 60Amp plugs, how did you connect it to your house? I haven’t found a premade cord and manufacturers want you to buy the plug to install on #4/4 section of cord. That’s fine but what about the other end? Is it wired to the breaker or do you have an external plug?

Do you know your well pumps nameplate ratings?

A 2hp induction motor may well exceed the 13,000 kW surge rating on when starting.

 

[arcteryx]

I posted a thread in Rural asking about a soft start on a well pump. In short, there was not a good solution that I was comfortable with, so I will leave it as is. I do have an Easy start for the AC, the two of these are the largest consumers.

On the pump, inrush is 42Amps @ 240, which is 10080W, and settles at about 22Amps. I have a large cistern so the well pump may only run once per week. I will also perform load management, so if I need to fill the cistern, the rest of the items will be turned off to run the pump.

 

[Vigo327]

If you think its going to void your warranty and you care about that i would just switch brands. If not i would just get it and move on with life as im ~98% certain its just going to work fine.

I suspect the issue has more to do with how far the hz will drop as the tractor adjusts to the load, than it has to do with any damage to the generator head windings. That really only matters if there are other sensitive appliances being powered at the same time.

 

[Chewwy]

I posted a thread in Rural asking about a soft start on a well pump. In short, there was not a good solution that I was comfortable with, so I will leave it as is. I do have an Easy start for the AC, the two of these are the largest consumers.

On the pump, inrush is 42Amps @ 240, which is 10080W, and settles at about 22Amps. I have a large cistern so the well pump may only run once per week. I will also perform load management, so if I need to fill the cistern, the rest of the items will be turned off to run the pump.

Typical clamp on current meters are just not capable of accurately measuring inrush current. The peak inrush is usually over before the meters start to detect it.

Your measured running load is 22 Amps. Inrush is typically around 6 times that. 132 Amps amps at 240 V is far greater than the surge rating of the Northstar generaor you were looking at.