Powerline Listeroid with 7.5 ST head issues with invertor transfer

[DirtMerchant]

I have Prosine 2.0 inverter that has a 110vac circuit that when energized will cause the inverter to stop inverting and let the electricity flow through it and it will start charging the batteries. This works very well when I power this circuit with my crappy harbor freight 3500watt generator. But when I do this with the listeroid  it just flickers, tries to charge and then stops the charging and goes back to inverting....

The listeroid is wired for 110, is producing 125vac at 59hz I am wondering if it is too much voltage or if the power is just too "dirty" ?

Any help would be appreciated !

[mike90045]

I wonder if a 100w bulb, as a load on the ST head, will help .    It may be you have to tweak the RPM to get 60.0 before it will sync, but thats being real picky.   

[BruceM]

The inverter may not be impressed with the varying frequency, the varying voltage or the spikes on the waveform, or the "harmonic hump".

If you are using the stock harmonic, it may work if you switch to an AVR off of the mains. That would eliminate the harmonic hump, and keep the voltage more stable.  Frequency will still vary due to low speed power stroke.

You could first try a 40-60uF motor run capacitor across the line output and hope the problem was the spikes and ratcheting of the waveform.

Good luck!
Bruce

[LowGear]

Same generator or both different engine and generator?

Casey

[DirtMerchant]

Same generator or both different engine and generator?

Casey

They are both completely different generators.

[DirtMerchant]

I wonder if a 100w bulb, as a load on the ST head, will help .    It may be you have to tweak the RPM to get 60.0 before it will sync, but thats being real picky.   

I'll have to try that tomorrow, I only had a kill-a-watt meter on it and the inverter plugged, I will try it with a few different loads and see if that helps it.

[DirtMerchant]

The inverter may not be impressed with the varying frequency, the varying voltage or the spikes on the waveform, or the "harmonic hump".

If you are using the stock harmonic, it may work if you switch to an AVR off of the mains. That would eliminate the harmonic hump, and keep the voltage more stable.  Frequency will still vary due to low speed power stroke.

You could first try a 40-60uF motor run capacitor across the line output and hope the problem was the spikes and ratcheting of the waveform.

Good luck!
Bruce

From what I have heard about the stock AVR, I should probably order a new one regardless, if just to have it on the shelf.

[BruceM]

Typically the ST's have no AVR, just excitation by the Harmonic winding which is somewhat self regulating.
Does your ST-7.5 have an AVR? 

[DirtMerchant]

Typically the ST's have no AVR, just excitation by the Harmonic winding which is somewhat self regulating.
Does your ST-7.5 have an AVR? 

Here is a photo of the AVR it came with already wired and mounted.

[Thob]

Looking at the links on ST7.5, it appears to be wired for 240V to me.  You will get 120V from the center links to either end, but I think you'll find 240V from end to end.  I don't think that has any effect on your problem, however.  It could overload the single winding if you attempt to get more than 3.75KW out of it, and it may cause the ST7.5 to buzz under load.

[BruceM]

Thob's observation is very important-  if the output is set up as 240 with a neutral, you will not get good regulation on a single leg with an imbalanced load.  Please confirm what your generators ouput is currently configured to, and what you actually need, and we could help point you in the right direction re: rewiring and getting better regulation. You could confirm that this is the problem by monitoring the voltage under load, with a true RMS AC voltage meter.

Another problem that can cause voltage issues is that if your inverter/charger presents as a very poor power factor load, the AVR may not regulate properly.  Again, check the voltage under load with a true RMS voltage meter.

Your AVR seems to be wired with excitation from the harmonic winding. I wish the vendors wouldn't do that.
This is not as effective for tight voltage regulation as using the line voltage for excitation instead of the harmonic, as for some units, the harmonic ouput is barely adequate.  The AVR can only DOWN regulate from the excitation source. So for some units the harmonic ouput just isn't enough to compensate for the voltage sag during the compression stroke. * The harmonic winding on the single phase units is also known to cause a "hump" on the AC waveform.  Its bad enough on some units (there's a lot of variation) to confuse a digital frequency meter (or perhaps your inverter/charger unit).

One thing that might help would be to contact the inverter/charger manufacturer and find out what their specs are regarding voltage and frequency. If some idiot tells you 60Hz and 120V, try to get a new idiot, because it should be a range.  They should be tolerant for a generator, but may see the normal frequency variation from a low speed engine as an impending shut down situation.  Or it's just getting confused because of spikes on the AC (which the motor run capacitor will help greatly).

Adding a load, as Tom suggested, and adding the motor run capacitor would be a good place to start.  

Good chance that with some effort and experimenting you can get this fixed without any real expense.

Best Wishes,
Bruce

* AVRs help with the normal power stroke flicker (voltage and frequency variation) on incandescent bulbs, but they have a harder time doing so for the larger heads; it will not help anywhere near as much on the ST 7.5 as it would on ST-5 or  ST-3.  The reason is the much larger inductance of the ST 7.5 rotor- it will be much slower to change.  There's a reason Lister put those massive flywheels on the SOM.  I wish our Rajkot suppliers would start making them!







  

[mobile_bob]

interesting thread...

i remember the APC ups systems having a setting that enables the unit to operate under
very tight to quite loose line voltages and hz variation.

apparently they figured some equipment needs really high quality line power, so if this is found to be not the case the inverter takes over.

if on the other hand the line power is a bit loose in spec and the loads serviced by it are not that particular the inverter can be switched up or down to accommodate what the load needs based on the power quality available, thus allowing the line power to pass through without kicking on the inverter.

it might be your inverter can be set to accept a bit looser power standards provided by the 6/1 and st7.5

if the inverter is set to pass only 60 hz +/- .2 hz or something it likely will never allow the 6/1 power to pass through. if on the other hand it can be reset to accept maybe +/-  1hz or so, maybe it will work out for you?

just a question i would be asking the inverter engineering dept

fwiw
bob g

[DirtMerchant]

 That is actually an older pic of the AVR and I have since changed it to 120vac,  I did try putting a load on the generator and the same issue occurred, the only difference was that the inverter stayed charging a tiny bit longer before it kicked back to inverting.

 So further testing ensued, I brought out the Harbor Freight 3500 and tried it, it worked for a few minutes but was heavily loaded until the circuit breaker on it kicked out. I reset the circuit breaker on the generator and tried again, then looked at the inverter screen and found the inverter was charging 13.5vdc @ 105amps  and powering the shop lights at roughly 22amps , apparently the load on the 120 side was over 20amps as it kept tripping the circuit breaker. After noticing this seems to be a load issue,  I returned to the powerline and realized the Kill-aWatt meter is only rated to 15amps and I was pulling in excess of 20amps through it, certainly not helping.  Disconnected the kill-awatt meter and tried again, this increased the time of the cutout but still not working properly. These tests showed that the issue was not entirely due to my Powerline's output as the Harbor Freight generator was having issues too. 

After all of this I finally read the manual on the inverter today, as it turns out there are a couple important settings that can create this issue, first as Mobile-Bob mentioned, you can set the width of tolerance on the incoming voltage & frequency, I had not done this so it is probably set too tight for the generator. Second important setting is the breaker size, pretty sure I have it set for 30amps,  which would be a setting for a 3000watt+ generator, according to the manual the charger will adjust its pull on the generator based on this breaker setting.

All of my gear is located at my up north property so I will bring the manual next weekend and try again but this time changing the settings so I don't pull so much power and widen the AC tolerance and see if it will behave.





 

[BruceM]

Nice troubleshooting, dirtmmerchant. Seems Bob G called this one right.

[DirtMerchant]

Nice troubleshooting, dirtmmerchant. Seems Bob G called this one right.

Yup Bob had it right, I re-programmed the inverter and set the breaker setting to 15amps and opened up the tolerance on the cycles and voltage, now the inverter charges at 65amps while running off the Listeroid, alas my CFL bulbs flicker when its running, thinking the cycle too low under load (55hz) I'll need to play with the governor when I have a bit more time with it and see if I can find a cycle it can hold without flickering the lights.

Once all of that is done and working properly I will move on to the real project of the inverter calling the listeroid to auto start when the batteries get too low.