Eletro magnetic clutch for watermaker pump

[Hoghead]

I have had it with the 12V powersucking, feeble output, Little Wonder watermaker and am thinking of a genset driven CAT pump and larger membrane

This pump will draw 4 HP and I will need a magnetic clutch fitted so that I can control on/off.
While I have used these clutches, I have never designed a system for one and would appreciate info on which one to buy.

Pump shaft is 20mm. Would something as simple as an auto aircon clutch work?

Gearing is an issue as I need to spin the pump at 1190 RPM to yield 5 USG/min
Single or dual belts? - I would love a gear belt!!

[Tellie]

Originally Posted by Hoghead

I have had it with the 12V powersucking, feeble output, Little Wonder watermaker and am thinking of a genset driven CAT pump and larger membrane

This pump will draw 4 HP and I will need a magnetic clutch fitted so that I can control on/off.
While I have used these clutches, I have never designed a system for one and would appreciate info on which one to buy.

Pump shaft is 20mm. Would something as simple as an auto aircon clutch work?

Gearing is an issue as I need to spin the pump at 1190 RPM to yield 5 USG/min
Single or dual belts? - I would love a gear belt!!

If you are going to go down this road, save yourself a lot of time and aggravation. Call Rich Boren at Cruise RO (619) 609-3432

www.HaldenMarineService.com

[Hoghead]

Will do

The simple way is to use a CAT pump directly mounted to an AC motor - no pulleys or belts!

A genset is part of this project and I am looking at a NextGen 5.5 kW unit with 21A output at 230V
The genset will power a 3 HP motor at 16A and give me 4 USG/Min. Unfortunately it does not have the 23A for a 5 HP motor.

Cheaper and simpler so maybe time for a rethink?

[Tellie]

Originally Posted by Hoghead

Will do

The simple way is to use a CAT pump directly mounted to an AC motor - no pulleys or belts!

A genset is part of this project and I am looking at a NextGen 5.5 kW unit with 21A output at 230V
The genset will power a 3 HP motor at 16A and give me 4 USG/Min. Unfortunately it does not have the 23A for a 5 HP motor.

Cheaper and simpler so maybe time for a rethink?

4 USG/min? (4 gallons a minute?) Are you talking pump flow or product water made?

[Hoghead]

Pump output

[exkma367]

We used a General tt9111 pump and one 2.5 x 40 membrane running of a pulley on the front of our Atomic4. No clutch, just stopped the motor, loosened the pump mount, attached the belt, tightened the mount and started the motor. We produced 16 gallons an hour. With the same pump we could have made 30GPH with an additional membrane. We did flush with fresh water after each run and had no problems in two years. This pump is impractical for a electric motor due to HP requirements.

[S/V Alchemy]

Originally Posted by exkma367

We used a General tt9111 pump and one 2.5 x 40 membrane running of a pulley on the front of our Atomic4. No clutch, just stopped the motor, loosened the pump mount, attached the belt, tightened the mount and started the motor. We produced 16 gallons an hour. With the same pump we could have made 30GPH with an additional membrane. We did flush with fresh water after each run and had no problems in two years. This pump is impractical for a electric motor due to HP requirements.

I must say that as an Atomic 4 owner, this is the most ambitious use of its power take-off that I can recall, and I know people who've rigged old bus heater blocks to get warm air venting and other modern conveniences from these venerable motors. I've never heard of an A4 watermaker.

[svJasmine]

Exkma,

Was the pump mounted to the engine? I would like to mount the pump off to the side in the engine room. I have often thought about that same thing, but with my yanmar. Seems like with a flat belt and an idler, I could put my cat pump off to the side.

Put the belt on, make some water and charge the batteries at the same time. More load for the diesel.

[a64pilot]

Put an arm on a spring loaded idler and it would only take a few seconds to remove the belt without tools too.


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[Offshore1960]

It's very common to run belt driven pumps off the main engine on small commercial fishing boats. You could easily set up a Pitt's electric clutch on the water maker pump and drive that with a belt off the front crankshaft pulley on the engine.

[Hoghead]

I have come full circle and am going to use a directed mounted CAT 350W pump on a Baldor 240V, 184TC frame, single phase, 3 HP motor. The two bolt right up so no pullies or belts
My boat is 240V

Current draw is 16A so no problem with the gennie output at 21A. By lowering pump pressure to 800 psi I will need 2.73 HP and this fits well with the RO membranes. I will be able to run nothing else when making water

If I mount the CAT pump on the gennie it draws 3 HP from the 11 HP total output. Not as bad but still limited in what I can run at the same time anyway.

Cheaper than using the electromagnet clutch, and easy. Granted when the electric motor is running my ability to run other 240V things is limited, however, I will only need the RO pump for an hour every other day, or worst case with guests every day.

[Hoghead]

Two full circles and back to the clutch as my 21A at 230V genset will not start the motor. Difficult to believe but a Leeson cap start/run 3 HP motor takes 90A to start!!

So............... what to use for a clutch?
CAT pump shaft diameter is 20mm

[phorvati]

Originally Posted by S/V Alchemy

I must say that as an Atomic 4 owner, this is the most ambitious use of its power take-off that I can recall, and I know people who've rigged old bus heater blocks to get warm air venting and other modern conveniences from these venerable motors. I've never heard of an A4 watermaker.

I have used atomic 4 to drive the WM pump clutch for about two years 2010/2011. I had two 2.4x40" membranes in series and later on in parallel.(after upgrading the pump). I will say that driving a cat 290 with a belt off front pulley took a toll on atomic 4 bearings. It really sped up deterioration. When i switched over to Westerbeake 40, I took atomic 4 apart and there were some signs of heavy wear and tear. I am saying this as a person with decent knowledge in A4s. (rebuilt two different Atomic 4s in the past). The findings explain prior observations of drop in engine oil pressure under load. This could have been from over tightening the WM drive belt.
If I had to do it again with an A4, knowing how end caps and connecting rods are mated, I would say try to setup an idler pulley to take the slack off the belt. i was taking slack off by tightening the belt which in turn put more stress on the bearings. Idler pulley would allow you to not have to put as much belt tension and it will hopefully not contribute to potential A4 bearing deterioration.
In terms of diesels, and i can only speak for W40, I noticed that connecting rod ends are dovetailed on the end caps which makes things more resilient to the kinds off of things we are likely to drive off of the front pulley.

[Tellie]

Originally Posted by phorvati

I have used atomic 4 to drive the WM pump clutch for about two years 2010/2011. I had two 2.4x40" membranes in series and later on in parallel.(after upgrading the pump). I will say that driving a cat 290 with a belt off front pulley took a toll on atomic 4 bearings. It really sped up deterioration. When i switched over to Westerbeake 40, I took atomic 4 apart and there were some signs of heavy wear and tear. I am saying this as a person with decent knowledge in A4s. (rebuilt two different Atomic 4s in the past). The findings explain prior observations of drop in engine oil pressure under load. This could have been from over tightening the WM drive belt.
If I had to do it again with an A4, knowing how end caps and connecting rods are mated, I would say try to setup an idler pulley to take the slack off the belt. i was taking slack off by tightening the belt which in turn put more stress on the bearings. Idler pulley would allow you to not have to put as much belt tension and it will hopefully not contribute to potential A4 bearing deterioration.
In terms of diesels, and i can only speak for W40, I noticed that connecting rod ends are dovetailed on the end caps which makes things more resilient to the kinds off of things we are likely to drive off of the front pulley.

Thanks for posting this phorvati. It is very good information and DIYers should take close take heed. While it may seem like a no brainer at first to use a boats engine to strap a high pressure pump to. It is fraught with many issues. There are very good reasons that all the major watermaker companies don't make engine mounted watermakers.

Halden Marine Services | Marine Watermakers, Solar Panels, Wind Generators

[Cheechako]

I remodeled my 120V AC water maker into engine driven. It had a Cat pump I mounted on the engine. It was pretty easy to find a 12V clutch for the Cat pump. Is yours tapered shaft or straight shaft? Metric or inch shaft?


My original AC unit was 1.5 HP direct driven. It had 3 membranes and put out 25 GPH water.