Need Help! Fischer Panda Generator

[tomicante]

Thanks for your answers!

I took off all other loads, and also tried to hook up the compressor directly to the generator with a 50amp breaker. The breaker doesn't trip, but the comressor stops after a couple of seconds.
I also thought that I might have used too small gauge wires as it is a long run from the generator to the compressor (35 feet of AWG 10), but after I hooked up directly without the long wire and it's still the same...

Before purchasing the compressor I've checked the current rating, which is 29 amps, so even if the starting current is double, my 6KW genset should be enough...

I'm browsing on the internet for solutions and I might have found something:
Elimia Air Compressor Motor Starter 5 15 20 HP 240V 36A - eBay (item 110656443587 end time May-01-11 14:02:07 PDT)
Anybody knows how this thing works? Is there a chance that this will eliminate my problem?

I also read that it's possible to change the capacitors in the generator for bigger ones, so it will be able to hold the starting current needed...

I appreciate all advice!!!

Thanks,
Tamas

[tomicante]

About the inverter...
How can I sync the inverter and the genset?
I thought the inverter will shut down if power comes from the generator.

I have 2 inverters:
1.) MAGNUM true sine wave charger/inverter (100amp/2000W)
2.) XANTREX 1800W inverter

Thanks,
Tamas

[GordMay]

Originally Posted by tomicante

... Before purchasing the compressor I've checked the current rating, which is 29 amps, so even if the starting current is double, my 6KW genset should be enough ...

Compressor motor starting currents are generally 6 - 8 times running current.

[tomicante]

Wow...

The compressor has a capacitor too which probably lowers the needed staring current, so it looks like I just need a little more boost. Playing with it for a day now it started twice. Once it starts no problem with running.

Thanks,
T.

[Highlander40]

29A ? Thats huge!
Starting an AC unit that draws 12A would make the 6kw Panda grunt for a second.
That motor is almost 2 HP! I think 16A is about 1HP.
Just too big!

[tomicante]

It's 2,2KW (about 3HP)...

I've found this on the Fischer-Panda site:

ASB-Automatic Start Booster

An electronically controlled high starting current in the control box. Suitable for all Panda asynchronous generators, to compensate the high starting current of electric motors (i.e air conditioning units etc). ASB should always be chosen if a generator is to be driven by an inductive load (electric motors, air-conditioning units etc). All generators from Panda 8000 up to Panda 14.000 are fitted, as a rule, with ASB as standard.

Mine is a smaller unit (Panda 6000), so originally it's not fitted with this booster. I will see if it's compatible with my unit...

Thanks!

[atoll]

6kw/240 v=25 amps
29 amps/240 v= 6950 watts plus shunt =+/- 12000 watts.
get a bigger genset

[tomicante]

It's 6KW/120V=50A.

[tomicante]

...and the 3HP motor is only 2,2KW = 18A (startup maybe double)...
The factory current rating is 29A, but it doesn't say if it's continous. For me it seems that 29A would be the startup current and I calculate 18A continous.
What do you think?

[CarlF]

The inverter solution would be to replace one of your inverters with something like the Victron Multiplus inverter/charger. Depending on size about $1600-$2500. These allow the genset power to pass through and when the AC load exceeds a user setting the batteries instantly provide additional amps via the inverter. This can be an additional 3000 watts added to whatever the genset is providing.

This would also let you set the maximum load on the genset to something less than 100% rating which will extend the genset's life.

The Victrons have a lot of other interesting features but it's a fairly pricey solution. Might still be the best idea in the long run. It's top quality gear.

MultiPlus 800VA - 5kVA - Victron Energy


Carl

[tomicante]

Thanks, but I've just installed a new charger/inverter, so that would be too pricy solution...
What about a hard start kit (capacitor and relay): Search hard start Hard Start Kits%2C - Grainger Industrial Supply
Do you think it might work?

[tomicante]

The compressor manufacturer says that it should run from a 4Kw genset as it has an in buildt capacitor for the startup...

[s/v Jedi]

Just don't get me started on Fisher Panda gensets... mechanics didn't even want to come near it when mine needed repair. In the end, I had to pay to get it removed from the boat, instead of trading it in for the new Northern Lights ! (this will surely get the pro-FP crowd to post and tell us how good and advanced these units are :-)

I completely agree with CarlF... get a Victron charger/inverter.

You write you don't want a Victron because you just bought something else... but at some point you must start to understand that it's just not gonna work with stuff like what you have/buy. A 6kW Northern Lights genset will run your compressor... your Fisher Panda helped by a Victron "Power Assist" unit (with decent battery bank) will run your compressor. That's two solutions to your problem; I'm afraid there's not gonna be a solution where you don't have to change anything.

ciao!
Nick.

[CharlieJ]

...and the 3HP motor is only 2,2KW = 18A (startup maybe double)...

As Gord and others have said, start-up current of a electric motor is an instantaneous 6 to 8 times the full load amps (FLA) rating.

This high current can be mitigated by the addition of a starting capacitor that is in the circuit as the motor starts and comes up to speed and then is switched out of the circuit by a centrifugal switch. A separate run capacitor is always in the circuit to reduce the effects of the running inductive load on the generator.

There are "permanent capacitors" that perform both the start and run functions but these are used on fractional hp motors.

My guess is that the compressor motor has a run capacitor, not a start capacitor. If this is true then changing this capacitor will have no effect on the start up behavior.

The least expensive way out of the generator/compressor mismatch may be to simply change out the compressor motor for one with both a starting and running capacitors.

The compressor manufacturer says that it should run from a 4Kw genset as it has an in buildt capacitor for the startup...

Based on the fact that the compressor won't start when power is provided by a genset that meets the compressor mfgr's. specs., I do not think that you have a starting capacitor but you have been given some misinformation from the mfgr. Does the motor have two capacitors mounted on it?

Have you attempted to start the compressor while on shore power? What were the results?

Do you have access to a clamp on ammeter with surge capture capability?

What is the mfgr. and model number of the compressor?

Charlie

[tomicante]

First of all thanks a lot for everybody trying to help me out with this problem! I really appreciate it!

So the comressor is a Coltri Sub MCH-6 EM, 115VAC, single phase, 3HP, 29 Amps continous and 87Amps starting current. and it has 2 capacitors (160mF and 315mF).
My genset's peak is about 80A for a short time, so it's pretty close...
See manufacturer's site: Aerotecnica Coltri - Portable Compressors - MCH-6/EM
I've tried to run it from shore power and it works fine, but from the generator it only moves for a couple of seconds.
I've checked many options on the net, and my last hope is a soft starter. The problem with it that there aren't many single phase soft starters on the market, or they are pretty expensive. The cheapest one is around 1000$.

Thanks,
Tamas