small compressor installed on a boat?

[happy-diver]

100 L/min about US 2-2.5k from my company, 2k hrs service kit US 850

View attachment 916993

What if I buy the compressor for the service kit and part out the compressor to make the parts kit cheaper

Are your parts genuine Bauer interchangeable dude

 

[Atta]

Everything is electrically fine, but it's questionable whether this is good for the compressor.

1.) Due to the low RPM of the compressor from the chosen gear ratio, the cooling is weak.
An additional electric fan may be required here.
2.) There could be issues with lubrication.
3.) There could be oscillation problems.

Both of these may not be the case, but operating the compressor at half rpm puts it outside the usual range. The compressor manufacturer Mohnsam warned me about this.

Bauer offers the Junior II in a lower power option probably for USA 120v users so they can run it on a typical home circuit. That model comes with a 2HP motor. It's the JRII-E1-2HP and the motor is run at 1400 RPM. So maybe the example in the YT video is closer to that? It would be interesting to know if the cooling fan or anything else is different. I'm looking at the list of Junior II models on:

Portables | Bauer Compressors

Portable scuba compressor with an air purification system and fill hose

www.bauercomp.com

 

[CG43]

Hello

Okay, very good, you may also operate the compressor at 1400 RPM.

The specified speed is the speed of the compressor.
To be sure, the example JR-E3 at 2100 RPM:
At 60Hz, the synchronous RPM would be either 3600 RPM or 1800 RPM.
2100 is higher than 1800, so only 3600 RPM can be considered as the synchronous speed.
However, that would mean a slip of (3600-2100) /3600 = 0.42.
Since slip directly reduces efficiency, the motor would have an efficiency significantly worse than 0.58.
This is unrealistic for a three-phase motor of this size.
Therefore, only the compressor RPM should be considered.

 

[Atta]

@CG43 What motor would you use if you wanted to have a 3 phase one (with VFD) with a 230v 50hz power source and running the compressor at 2100 RPM? I don't understand the efficiency parts with the VFD (I'll go google to try to learn more). And how much more efficient would that be over using the single phase 230v motor already on the compressor?

 

[CG43]

Hello Atta !

If you find a power specification on the nameplate of the motor, it is the output power.
For 2100 RPM, you need 2.2 KW.
Next, you need the power consumption of the motor.
The input power is calculated for a single-phase motor as: P = U * I * cos phi (power factor).
For a three-phase motor: P = U * I * cos phi * square root 3 (= 1.732).

Whether you can get a VFD that provides the necessary power and can start a single-phase motor at an acceptable price is very questionable.
On the other hand, you can get a suitable three-phase motor very cheaply in the EU and probably also in the US . Three-phase motor is the best solution may be the only one .

 

[iain/hsm]

@CG43 What motor would you use if you wanted to have a 3 phase one (with VFD) with a 230v 50hz power source and running the compressor at 2100 RPM? I don't understand the efficiency parts with the VFD (I'll go google to try to learn more). And how much more efficient would that be over using the single phase 230v motor already on the compressor?

To add to your headache I should offer some better information than in my last post.

Your next hurdle is what is called Efficiency Rating.
Each and every motor both in Europe under (IEC/EN) and USA under NEMA EISA and EEV in Canada
has an efficiency rating and you need to choose a suitable efficiency rating.

We typically use IE 3 Premium Rating for all compressors in Europe and in USA the same premium but under the NEMA rating. The IE3 is 84.2% efficient compared to the IE1 which is only 79.7% efficient on a small 2.2Kw motor.

I have enclosed below the ABB Motor IEC 60034-30-1 published standards to add to your brain loading.

Also for use on a yacht your other consideration is the IP rating. Or water ingress protection. This is the water ingress protection rating and again available both under IEC or NEMA also enclosed below.
You don't want to add electrocution to the hazards of running a compressor on rolling deck yourself when the deck is awash.

For example a NEMA drip proof motor would not be suitable for a Yacht IMHO (this is similar to our IEC rating of IP22) By contrast a Washdown rated motor might be a tad overkill. Offshore on oil rigs and vessels EEx e is also typical with a high IP66 or IP67 ratings.

Below the IP water ingress protection rating web site

https://www.iec.ch/ip-ratings

Below the ABB Motor Efficiency rating in PDF

 

[JohnN]

One of my never-gonna-happen pipedreams is to
retire
sell it all
buy a liveaboard boat
and explore

a random thought pops into my head this morning about my pipedream on a liveaboard
I would ideally need a small compressor onboard. It wouldn't need to be a fast fill.

A long time ago I was certified as a nitrox and trimix blender, but I never really got into the weeds of maintaining and operating the compressor. I just remember it being a rather high-maintenance thing.... service intervals, filters, etc... but I never got into the weeds of it

so crude ballpark cost for a small compressor for that sort of application?
and what sort of ongoing maintenance/service is required for such a thing?

An alternative not yet mentioned would be to find a RIX SA-3 on the used market

No more oil changes or filters to worry about

Here is an old old post from our favorite curmudgeon:
RIX SA-3E Compressor 60Hz Motor Drive Configurations

I personally have a SA-3 and find it similar to the legendary “bees knees”

 

[BRT]

Hello

Okay, very good, you may also operate the compressor at 1400 RPM.

The specified speed is the speed of the compressor.
To be sure, the example JR-E3 at 2100 RPM:
At 60Hz, the synchronous RPM would be either 3600 RPM or 1800 RPM.
2100 is higher than 1800, so only 3600 RPM can be considered as the synchronous speed.
However, that would mean a slip of (3600-2100) /3600 = 0.42.
Since slip directly reduces efficiency, the motor would have an efficiency significantly worse than 0.58.
This is unrealistic for a three-phase motor of this size.
Therefore, only the compressor RPM should be considered.

They are belt drive. You can run the compressor at any RPM you want to.

 

[iain/hsm]

Now as far as motor brands are concerned the two best brands of motor by far are ABB Sweden and Siemens Germany.

The worst are normally found on small portable sports scuba compressors and are SOGA (Italy) or anything made in China. Go figure LOL

Once you narrow down the brand and EFF rating that raw untreated steel drive shaft off the motor needs your attention. Or six weeks in and it's already turned into rust.

A horrible brown wax spray I cant remember its name but you spray it on or paint it on and the solvent evaporates off and your left with a brown waxy coating. Again not the junk you get in car parts shops.

Again we use it offshore (Now i've got it ) Corroless CCI 400
Safety data sheet below

 

[iain/hsm]

They are belt drive. You can run the compressor at any RPM you want to.

I'm sorry but that statement is simply not true and for multiple reasons.

1. You have a splash lubricated crankcase on the Bauer Junior 11. As with many other small oil lubricated portable compressors. Some of the larger units may even have an oil pump known as a gearoter pump but again all types of oil lubricated compressor are subject to RPM.

Too slow an RPM and the oil slinger doesn't fling enough oil up from out of the sump and onto the moving parts or by another example take the gearoter mechanism type on the Oceanic when running too slow this hasn't got enough RPM to create enough oil pressure to pump the oil out of the sump and up onto the moving parts the crankshaft bearings, conrod, guide cylinders and pistons etc if running too slow.

2. The inclination of the pump on a rolling deck is another hugely damaging consideration for small portable compressors on a yacht.
Further take say the Coltri MCH6 and their new ICON range these only have a 5 degree and a 6 degree angle of inclination in a stationary position on land any more in one plane and there is in effect no oil in the sump and that coupled with a low RPM is a huge bill a comin. Take the other angles on a yacht the pitch and roll aspects and too much oil slugs up with a hydraulic lock risk conversely the other extreme of the angle incline is oil starvation.

3. Also you need to achieve sufficient cooling and the fan is directly affected by the RPM
Again for offshore we change the pitch angle of the fan blades and the number of fan blades depending on the ambient air temperatures location flow and pressure but again critically the RPM

So I trust you appreciate that while there is granted a very small narrow band range of RPM available it is critical not to under run or over run these limiting factors in a typical oil lubricated recreational sports scuba compressor.