Upgrading Bauer Junior 2: motor?

[o-ren-ishii]

Hi all,


Currently I have a Bauer Junior 2 to fill my own nitrox. It's a very portable system which I can take to the caves as well ... but.. is very slow.
So I'm thinking about upgrading to for instance a bauer Mariner, Alkin Mariner W31 or something similar. Unfortunately most of these units either are pretty big or require 3-phase power. I don't have 3-phase near diving locations so that's not really not the best option.


I've noticed the Bauer Oceanus has a 3kW motor instead of the Junior's 2.2kW. Would it be a option to take a 3kW motor and replace the Junior's motor with it? As far as I can see the Oceanus looks identical. The RPM is 2300 . The Junior I'm not 100% sure about, I see different RPMs on different websites.
The only thing I'm not sure about; if the RPM remains the same how can the Oceanus pump 140l/min while the Junior only does 100L/min? So I'm not sure increasing the power of the engine would actually help.


The second option would be to get a nice 3 Phase motor and a VFD to either run it 'slow' at home when I'm not in a hurry and as fast as possible when filling a bunch of tanks after a days project diving. This way it would also be a bit more friendly on the funky breakers near dive sites.

What do you guys think?

 

[tbone1004]

Moving to a 3-phase motor is not scary as you can feed it off of single phase if you use a VFD, this is a requirement for all new compressors in Europe these days. Very easy to do and I would recommend looking at that vs trying to overclock your current pump which is going to generate more heat and increase wear.

 

[stiebs]

I've noticed the Bauer Oceanus has a 3kW motor instead of the Junior's 2.2kW. Would it be a option to take a 3kW motor and replace the Junior's motor with it? As far as I can see the Oceanus looks identical. The RPM is 2300 . The Junior I'm not 100% sure about, I see different RPMs on different websites.
The only thing I'm not sure about; if the RPM remains the same how can the Oceanus pump 140l/min while the Junior only does 100L/min? So I'm not sure increasing the power of the engine would actually help.

I'm not compressor expert, but have been looking closely at the Jr2 and Oceanus. (have opted for the Oceanus, which I should have any day soon).

Both compressor blocks are rated for 2300rpm, but the Oceanus has a larger 1st stage bore than the Jr2 (70mm vs 60mm) so will work the driving motor harder. My limited compressor knowledge but general mechanical knowledge tells me that the same motor will drive the Jr2 faster than it would the Oceanus, pushing the Jr2 compressor block faster than intended.

(The diving motors are rated a nominal speed, and actual speed they run at will be dependent on the load that they are driving).

The other big difference between the Jr2 and Oceanus is that the Jr2 block has only 360ml of oil and does not have an oil pump. The Oceanus holds 1.3L of oil and has a basic crank-driven oil pump.

So driving the Jr2 faster will probably push it beyond its lubrication capacity.

 

[o-ren-ishii]

Thanks a lot guys!
Both of your replies were a bit in the direction I was thinking.

I couldn't find the inner specs for the Ocenanus so I kept wondering how one could do 140 instead of 100L/min. The bore explains a lot. I think you are right about the oil being an issue as well.

Good choice the Oceanus. Did you get one with auto-condensate discharge?

I'll leave the Junior be for now and might go for a slightly bigger 3-phase compressor capable of running on 1-phase with a VFD.

 

[Capt. Bas]

(The diving motors are rated a nominal speed, and actual speed they run at will be dependent on the load that they are driving).

Are you sure about that, a motor speed is related to the amount of poles and the frequency of the net.
It will keep the nominated rpm's till it gets overloaded and at that moment it starts creating a lot of heat and current and the fuse/overcurrent protection will cut out.
It is possible a single phase motor is running a higher RPM when fully unloaded. Driving a compressor gives enough load to make sure the rpm's are at the nominated rating.

 

[BRT]

Are you sure about that, a motor speed is related to the amount of poles and the frequency of the net.
It will keep the nominated rpm's till it gets overloaded and at that moment it starts creating a lot of heat and current and the fuse/overcurrent protection will cut out.
It is possible a single phase motor is running a higher RPM when fully unloaded. Driving a compressor gives enough load to make sure the rpm's are at the nominated rating.

Full load speed is the rated speed at the rated horsepower, but that is usually within 50 rpm or so of unloaded maximum speed.

 

[tbone1004]

Are you sure about that, a motor speed is related to the amount of poles and the frequency of the net.
It will keep the nominated rpm's till it gets overloaded and at that moment it starts creating a lot of heat and current and the fuse/overcurrent protection will cut out.
It is possible a single phase motor is running a higher RPM when fully unloaded. Driving a compressor gives enough load to make sure the rpm's are at the nominated rating.

that's not how AC motors work.... DC motors sure, but AC motors will run at their rated RPM whether loaded or unloaded. If it's overloaded and starts to bog down it will start creating a lot of heat and will trip out almost immediately because it can't run at its rated RPM