Variable speed Gensets, any good?

baylabayla3288

baylabayla3288

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Does anybody on the forum have experience of Whisper Power Genverters from Whisper Power. The original HFL 4kva in my Phantom 38 has converted into a smoke generator and is in need of replacement. I'm considering the Whisper Power M GV 4 which is based on a variable speed one cyl diesel engine - inverter design.

http://www.whisperpower.com/product/m-gv-4-basic/M3_C1_S84_P87_D14/

As I allready have a 2KW Combi Mastervolt inverter with a power boost function I can get a max output of 4-5 KW which is good enough for my use.

Are these as quiet as claimed? How about reliability?

Your views are highly appreciated.
 
Can't see the benefit of variable speed for the generator. The output at 240 v must be at 50 HZ, and this is directly proportional to the generator's speed - if a 2 pole then 3,000 RPM, 4 pole 1,500.

If you vary the frequency more than a small amount then you risk damaging anything connected on the other end.

The only benefit would be if the inverter is providing a constant frequency and voltage output, but slows the prime mover at lower power output, but it is vital the generator can output a reasonable pure sine wave AC form.

On a power boat the fuel economy benefits of the generator will at best be barely noticeable compared with what the engines will burn, therefore the KISS principle is being forgotten, and the more complex the piece of kit is the more difficult and / or expensive it will be to fix when it goes wrong.

I have a simple Mastervolt 4 kVA unit, and they want over £400 for a simple blister panel on the start fascia that they probably buy for around £10. What a manufacturer would charge to replace an inverter part - well ...
 
superheat6k said:
Can't see the benefit of variable speed for the generator. The output at 240 v must be at 50 HZ, and this is directly proportional to the generator's speed - if a 2 pole then 3,000 RPM, 4 pole 1,500.

If you vary the frequency more than a small amount then you risk damaging anything connected on the other end.

The only benefit would be if the inverter is providing a constant frequency and voltage output, but slows the prime mover at lower power output, but it is vital the generator can output a reasonable pure sine wave AC form.

On a power boat the fuel economy benefits of the generator will at best be barely noticeable compared with what the engines will burn, therefore the KISS principle is being forgotten, and the more complex the piece of kit is the more difficult and / or expensive it will be to fix when it goes wrong.

I have a simple Mastervolt 4 kVA unit, and they want over £400 for a simple blister panel on the start fascia that they probably buy for around £10. What a manufacturer would charge to replace an inverter part - well ...
Click to expand...

I can agree with the keep it simple argument, this is getting fairly complex.

The new Genverter genset from Whisperpower (a spinn off Company from Mastervolt) does actually have a DC alternator that is connected to an internal inverter to ensure really stable 230 V 50 Hz AC output. The diesel engine rpm varies with the needed power. The benefits of this is supposedly silent running, less emissions, optimally loaded diesel engine, longer service life and less fuel usage. In addition this model is fresh water cooled or actually oil cooled, so less internal corrosion and it comes with a nice metal sound shield. The drawback is lower output power compared to my current HFL 4kva. However my separate inverter should help with temporary peak loads of several minutes if needed.

In addition the price for the Genverter is offered at 5900€ while the Pugaro 5kva is 1k more from my local vendor in Finland. Any other fresh water cooled unit in this power range is 2k or more expencier.
 
baylabayla3288 said:
Does anybody on the forum have experience of Whisper Power Genverters from Whisper Power. The original HFL 4kva in my Phantom 38 has converted into a smoke generator and is in need of replacement. I'm considering the Whisper Power M GV 4 which is based on a variable speed one cyl diesel engine - inverter design.

http://www.whisperpower.com/product/m-gv-4-basic/M3_C1_S84_P87_D14/

As I allready have a 2KW Combi Mastervolt inverter with a power boost function I can get a max output of 4-5 KW which is good enough for my use.

Are these as quiet as claimed? How about reliability?

Your views are highly appreciated.
Click to expand...

Before I start I want to make it clear that I do work for one of the major Marine generator manufacturers, But I would like to give you my thoughts anyway.

For me it depends how many hours you run your generator each year?

The Whisper power Genverter uses a single cylinder air/oil cooled engine driving a permanent magnet generator, then a inverter converts this to 230VAC. the operating engine speed is between 2500 and 3400rpm.

With a single cylinder air/oil cooled engine running at these speeds, I suspect it is not going to be that quiet. (spec sheet does not give a sound level) or have a long serivicable life (compared to a slow speed generator). but if you only plan to do a 100hrs or so each year then it should give you good service.

however if you want a quiet, reliable and long lasting generator? I my opinion is to look at a slow speed 1500rpm generator from one of the main stream suppliers like - Northern Lights, Cummins Onan or Kohler.

The only downside is that the slow speed generators is that size & weight is greater than a high speed generator. also most slow speed generators start at 6/7kW which maybe to big for your application.

You should also think about fitted a exhaust gas water seperator into the system (if not already fitted) as this will cut the exhaust noise greatly.

Anthony
 
ARE said:
Before I start I want to make it clear that I do work for one of the major Marine generator manufacturers, But I would like to give you my thoughts anyway.

For me it depends how many hours you run your generator each year?

The Whisper power Genverter uses a single cylinder air/oil cooled engine driving a permanent magnet generator, then a inverter converts this to 230VAC. the operating engine speed is between 2500 and 3400rpm.

With a single cylinder air/oil cooled engine running at these speeds, I suspect it is not going to be that quiet. (spec sheet does not give a sound level) or have a long serivicable life (compared to a slow speed generator). but if you only plan to do a 100hrs or so each year then it should give you good service.

however if you want a quiet, reliable and long lasting generator? I my opinion is to look at a slow speed 1500rpm generator from one of the main stream suppliers like - Northern Lights, Cummins Onan or Kohler.

The only downside is that the slow speed generators is that size & weight is greater than a high speed generator. also most slow speed generators start at 6/7kW which maybe to big for your application.

You should also think about fitted a exhaust gas water seperator into the system (if not already fitted) as this will cut the exhaust noise greatly.

Anthony
Click to expand...


Hi and thanks for your reply. Yes I would really like to have a low rpm unit for examlpe Kohler however there is limited space available and therefore I'm only looking at the one cyl versions. Comparing with these the Whisper Genverter could potentially be a good choise. Because of the low annual usage, 50 - 100 hours, sound level, closed cooling (easy witerizing and low corrosion) and off course reliability are important criteria. The Pugaro would be straight forward plug in and play but very old fasion. Still if anybody has heard the noise level of the variable speed Whisper would be greate to get feedback.
 
baylabayla3288 said:
Hi and thanks for your reply. Yes I would really like to have a low rpm unit for examlpe Kohler however there is limited space available and therefore I'm only looking at the one cyl versions. Comparing with these the Whisper Genverter could potentially be a good choise. Because of the low annual usage, 50 - 100 hours, sound level, closed cooling (easy witerizing and low corrosion) and off course reliability are important criteria. The Pugaro would be straight forward plug in and play but very old fasion. Still if anybody has heard the noise level of the variable speed Whisper would be greate to get feedback.
Click to expand...

Just got the noise level info, low indeed:

-********* M-GV 4 Genverter Basic Marine

-********* M-GV 7i Marine 12V version


The level of noise depends on the rpm:


-********* 2400 rpm*********** 52 dba

-********* 3400 rpm*********** 58 dba
 
baylabayla3288 said:
Just got the noise level info, low indeed:

-********* M-GV 4 Genverter Basic Marine

-********* M-GV 7i Marine 12V version


The level of noise depends on the rpm:


-********* 2400 rpm*********** 52 dba

-********* 3400 rpm*********** 58 dba
Click to expand...


Do you know the distance for these figures? I suspect they will be 7m figures.

58dba@7m = 75dba@1m, so you need to be sure you are compairing noise levels at the same distance.

Anthony
 
I have a standard mastervolt whisper 3.5
Generally run about 60 hrs a year.
It's located in the engine room of a Turbo 36 A/C, as such we are directly
above the unit. Noise levels are very reasonable with very little vibration.
 
ARE said:
Do you know the distance for these figures? I suspect they will be 7m figures.

58dba@7m = 75dba@1m, so you need to be sure you are compairing noise levels at the same distance.

Anthony
Click to expand...

Unfortunately I do not know the distance. I would assume some standard methode is used. The actual noise level in the boat depends on many things however the soundhield is metal which is a goog starting point.
 
Don't just go by the dBA figures, also consider what the noise actually is.

1500 rpm might be a soothing rumble to you, and a minor annoyance to your battery powered neighbours.
3000 rpm could sound like an out-of-control lawnmower, or an elderly person attempting to park.
 
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