got bit by Power Factor !

[Mike90250]

yesterday, my pump would not stay running, the Motor Protector circuit kept shutting it off after 20 seconds. I tried cleaning the filter, and running the outlet into a bucket, minimal backpressure, and it would still shut off. I really did not like the idea of having to repair a bum system in the rain, Rain. Clouds. Generator. Pump always worked on the other 3Kw generator (1930's gear) But the new generator - won't run the pump. Something about the PF of the pump, and the lightweight rotor of the alternator. The Subaru/Hatz diesel genset is rated 3.3Kw peak, 3Kw cont. But it's so lightweight (my old alternator weighs more than the new genset) I seldom run it at more than 2.5Kw charging batteries,
Goes to show that sometimes small is too small. With no other loads or battery charging going on, I can barely run a 1/2 hp pump off a 3Kw genset. What a pain that Power Factor can be. I guess the motor protector circuit did not like something in the power quality and shut the pump down.

[Bala]

I would say there is a problem with the generator or the pump other than power factor.

probably not telling you anything you dont know

But, Check your generator / Hz - Engine RPM and make sure its governing to hold under load.

[Mike90250]

the RPM & voltage is fine. I just can't do anything else but run the pump (the inverter logs it at 1,000watts) but this new lightweight alternator gear apparently has no headroom for PF losses. The inverter qualifies it just fine as a generator and pulls full load from it. Going to have to add this to the generator stickies. Same generator will not run the control circuit of the gas oven. (burners on the same range OK) And the old '30s generator won't run the garage door opener.
Likely related to all the safety gadgets
IMG_20160302_102438817_HDR-c.jpg

[Bala]

You will have to school me a lot more in how this is a power factor problem.

You essentially have only about 1/3 load on the genset.

I know of power factor but not in detail.

I have had a fair bit to do with a lot of generators running a lot of things. I worked in a hire company as a mechanic and we had an in house electrician.

I would still be thinking a problem with the generator or the pump.

pooring rain hers so have my main genset on right now. 10kva twin cyl lister with stamford.

[jflorey2]

Something about the PF of the pump, and the lightweight rotor of the alternator.

Can you get/borrow a scope and look at V/I curves? That would probably tell you a lot about what's wrong. My guess would be high harmonic content (i.e. gets square-wavey or peaky) when the load gets inductive (i.e. when the pump turns on and gets to speed.) If that's the problem, some additional capacitance between the pump switch and the pump might help.
PS; if either harmonics or voltage sag cause high current that will trip the motor protector even if the overall wattage stays low,
Try the other direction and choke off the pump flow with a valve.

[inetdog]

It is true that some generators cannot handle high inductive power factor. If that is the case PF correction caps are the best solution.
A lightly loaded motor will have a worse power factor than one at full load. Are you reducing the motor load by restricting the flow? '
Try adding a resistive load in parallel to see if that improves things.

[Sunking]

Can you get/borrow a scope and look at V/I curves? That would probably tell you a lot about what's wrong. My guess would be high harmonic content (i.e. gets square-wavey or peaky) when the load gets inductive (i.e. when the pump turns on and gets to speed.) If that's the problem, some additional capacitance between the pump switch and the pump might help.
PS; if either harmonics or voltage sag cause high current that will trip the motor protector even if the overall wattage stays low,
Try the other direction and choke off the pump flow with a valve.

Ditto.

Even though the KVA may be within range of the generator, the pump PF sounds like it falls outside the range of the generator. Do you know the generator spec PF. Something like .8 maybe? If you know the PF of the pump and KVA you can calculate and add a PF correction cap.

[inetdog]

Mike,

There are two ways that the PF can interact with the generator capability:

1. Generator is specified, for example, at 5kW, and 5400kVA at .8 PF. That can be telling you that the generator can produce the current corresponding to 5400kVA but the prime mover can only generate 5kW of real power continuously. In that case you could load it up with 2kW at a PF of .6 and still stay within both the total current and total real power limitations. If the generator were a rotating permanent magnet with no variable field or electronic voltage regulation that is a possibility. OR
2. Generator is specified at 5kW/5400kVA at; .8PF. If the generator has a lot of electronics, it could be telling you that the output will be unstable if loaded down with a PF lower than .8 no matter how low the total power is.
Real life will be somewhere in between these two limiting cases, and it is very difficult to tell where it lands based only on the specs on the line card for the product.
Your safest bet is to assume that you are operating under condition 2 and add PF correction capacitors downstream of the pump controller so that they are switched in and out with the motor.
Be warned that some generators (and inverters) will not tolerate any deviation from PF of 1.0 in the capacitive direction. The spec of PF = .8 really should be PF = .8 inductive for completeness.

[Sunking]

2. Generator is specified at 5kW/5400kVA at; .8PF. If the generator has a lot of electronics, it could be telling you that the output will be unstable if loaded down with a PF lower than .8 no matter how low the total power is.
Real life will be somewhere in between these two limiting cases, and it is very difficult to tell where it lands based only on the specs on the line card for the product.
Your safest bet is to assume that you are operating under condition 2 and add PF correction capacitors downstream of the pump controller so that they are switched in and out with the motor.
Be warned that some generators (and inverters) will not tolerate any deviation from PF of 1.0 in the capacitive direction. The spec of PF = .8 really should be PF = .8 inductive for completeness.

I suspect that is what is going on as reflected in my response. I would bet the genny he has is a PF = .8 with a Electronic Regulator throwing fits with something lower then .8PF

[jflorey2]

Be warned that some generators (and inverters) will not tolerate any deviation from PF of 1.0 in the capacitive direction. The spec of PF = .8 really should be PF = .8 inductive for completeness.

That's a very important point, and I would add that a capacitor bank that brings a motor back to a PF of ~1 while operating may result in a capacitive load during startup of the motor. In addition, induction motor power factor often changes with mechanical load, so (for example) refrigerator power factor may change as refrigerant pressures change.

[Mike90250]

It's a pretty simple basic alternator, and the pump has .76 PF. The Protector/Control box cannot tolerate any added capacitors, so I'm going to have to run within the limits,
now that I know what they are. The big ST alternator on the lister genset has a squirly waveform from the harmonic winding, but everything is happy with it, but the garage door opener. ( discussion about the windings in the head here http://www.microcogen.info/index.php?topic=1833.0 )
4" single phase 3 wire 1/2 hp in the chart

[MichaelK!]

yesterday, my pump would not stay running, the Motor Protector circuit kept shutting it off after 20 seconds.

Exactly what are you referring to when you talk about the "motor protection circuit". Are you referring to what Franklin Electric calls their "Main Overload" (part number 27511115)? I know you made the same reference to a response you gave me about my well pump.

[Mike90250]

It's a box from Franklin called Pump Protector. it's also an electronic starting module that you cannot play with a start cap.
The circuit detects running dry (too light of a load) closed valve / ice in the line (overload) and likely some over/under voltage stuff. When the power factor gets wonky, the box just shuts the pump off.

[MichaelK!]

It's a box from Franklin called Pump Protector. it's also an electronic starting module that you cannot play with a start cap.

Now I went to the Franklin Electric website, and found no reference at all to a "pump protector". Are you actually referring to what Franklin calls their "motor control box"? Does it look like this?
BTW, the "main overload" I referred to in the post above is that black cylinder in the photo directly under the L1 wire.

[Mike90250]

Nope, your photo is of a standard starter which nearly always includes the overload.

http://www.franklinwater.com/media/116153/M1409-Pumptec-Family-Brochure-01-14_WEB.pdf

Franklin Pump Protectors:

http://www.thepumpwarehouse.com/group.asp?grp=195

The Pumptec line of pump protectors from Franklin Electric are computer-based pump/motor protection devices which monitor load and power conditions to provide superior protection. They monitor and diagnose motor load to prevent pump or motor failure due to adverse conditions such as low-flow wells, pump damage, clogging, bound pump, or power mishaps.