Home Compressor suggestions

[gorlam36]

Ray:

I am looking for a compressor to install on a cruising boat. The boat is equipped with a 4kW diesel generator that can put out 120VAC, 1 phase at 33A. It can also be configured to put out 240VAC, 1 phase at 16A.

I am proposing using a VFD to drive a 3HP 3 phase motor in order to manage the startup loads as well as to be able to fine tune the compressor rpm without overloading the generator.

The compressor would be installed in the engine room and would need automatic drains and a snorkel to the outside. Blowers would be on to provide cooling.

Have you had any experience configuring a MCH-6 system this way?

Gord

 

[rjack321]

You couldn't pick a worse place to install it than engine room on a boat.

Engine rooms are hot and excess heat =
Dieseling of oil and CO production (this kills people every year)
Reduced oil life
Reduced compressor life (bearings and such)
Drastically reduced filter life.

You might think you can remove all the heat with fans but the reality is that you won't. Air doesn't have enough heat capacity to deal with engine, generator, and now compressor heat output.

As an alternative, consider putting it in a box on deck where you can open the lid and fold 2 or more sides of the box down to give it gobs of free air.

 

[rcontrera]

Ray:

I am looking for a compressor to install on a cruising boat. The boat is equipped with a 4kW diesel generator that can put out 120VAC, 1 phase at 33A. It can also be configured to put out 240VAC, 1 phase at 16A.

I am proposing using a VFD to drive a 3HP 3 phase motor in order to manage the startup loads as well as to be able to fine tune the compressor rpm without overloading the generator.

The compressor would be installed in the engine room and would need automatic drains and a snorkel to the outside. Blowers would be on to provide cooling.

Have you had any experience configuring a MCH-6 system this way?

Gord

You just described the stainless steel MarinePak version of the MCH6. The VFD allows operation of the three phase motor on a single phase system and put out 4.2 SCFM instead of 3.5 SCFM.

 

[h90]

You couldn't pick a worse place to install it than engine room on a boat.

Engine rooms are hot and excess heat =
Dieseling of oil and CO production (this kills people every year)
Reduced oil life
Reduced compressor life (bearings and such)
Drastically reduced filter life.

You might think you can remove all the heat with fans but the reality is that you won't. Air doesn't have enough heat capacity to deal with engine, generator, and now compressor heat output.

As an alternative, consider putting it in a box on deck where you can open the lid and fold 2 or more sides of the box down to give it gobs of free air.

I got told the MCH6 is already running hotter than comparable other units (Bauer). There is special Oil for hot environment but I doubt it helps very much. I would specially worry for the 4th stage life. Putting it outside is the way to go. Or in the captains place (don't know the English word). Or as it isn't very heavy, store it with the engine and take it up when you need it.

 

[Doc Harry]

Another reason for bank bottles is for late-night fills. Getting home late and leaving early in the morning doesn't always allow me to run my compressor to refill the cylinders. But with the banked gas I can quietly top off at any time of the day or night. And I no longer am getting bullet holes in my windows.

 

[rcontrera]

Just don't pump bulk bottles with the MCH6 or Junior II since you will shorten the life of the compressor drastically as neither are rated for continuous duty.

 

[h90]

Just don't pump bulk bottles with the MCH6 or Junior II since you will shorten the life of the compressor drastically as neither are rated for continuous duty.

Where I bought it, they told me (on the MCH6): 1 bottle or 2 bottles, than give it a break to cool down. Cool room, extra fan recommended. I don't know how it is for the MCH6 with 80 liter/min (the 1 phase electric) maybe it is a bit more stable?

I think 300 bar bank bottles will be the worst when it is for a long time between 200 and 300 bar.

 

[rcontrera]

While temperature is important, the real enemy of these little guys is sustained stress. When you fill individual bottles and then shift over to the next one, you can almost hear the compressor say "thank you". By cycling the pressure up and down, you are not tearing into the crank and bearings with a sustained load.

In order to lower the weight and price on the little guys, they have a pretty light weight crank and bearings. I have paintball customers that pump up their little bottles to 4500 psi all day long and their compressors are in excellent shape ... because they cycle. I have another that hooked their MCH6 to a three bottle cascade and it is showing metal dust in the oil each time they change it.

Heat=bad ............... Sustained load=badder

 

[h90]

While temperature is important, the real enemy of these little guys is sustained stress. When you fill individual bottles and then shift over to the next one, you can almost hear the compressor say "thank you". By cycling the pressure up and down, you are not tearing into the crank and bearings with a sustained load.

In order to lower the weight and price on the little guys, they have a pretty light weight crank and bearings. I have paintball customers that pump up their little bottles to 4500 psi all day long and their compressors are in excellent shape ... because they cycle. I have another that hooked their MCH6 to a three bottle cascade and it is showing metal dust in the oil each time they change it.

Heat=bad ............... Sustained load=badder

hmm thinking thinking....
If it is not the heat what is it? In a simple logic it should be the same if it moves x times with a given load (pressure) at one time or if split in several times. But it is not. The shop who sold me told almost exactly the same. Might be the reason that in continuous high load the crank and the bearing locally overheat and some points?? Just because they can't transfer the heat from the bearing away?
Just an idea.....

 

[Lobzilla]

Where can I get the solenoid valve for an auto-drain?