Dawn of the stealth dredge

[Phil]

All electric motors, including electric motors for a pump, have a maximum amp draw rating, which is the amperage when the motor is running. However, the problem you are running into pertains to the "inrush current", which is the amount of power required to get the motor spinning. On high efficiency motors, it can be as low as 1.5X the rated hp. For most, it is around 3X. In your situation, you are pulling a total of 20 amps for both motors once they are running, but to get them started, they need upwards of 60 amps.

I ran into the same problem building a portable conveyor powered by a gen. The solution was to use a three phase motor, wired to a variable frequency drive that uses single phase 120v on the input side, three phase on the output. Very efficient and it worked great. However, be sure to use an inverter gen because VFDs do not tolerate the high harmonics from normal generators.

Whatever you do, install at least two separate fuses/circuit breakers rated slightly above 10 amps, with a high inrush current (Fuse or breaker designed for motors). If your pontoon flips or sinks, they will trip and prevent you from being electrocuted.

 

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[LeeOregon]

Lee you need a "Vacuum gauge" to measure your suction from the pump / nozzle . I installed my vacuum gauge after my nozzle somewhere in your line , where ever it's convenient for you to install. Now I record what is the vacuum at various RPM's of the engine (or motor that your system is using . and when that's done I remove the gauge and plug the hole permanently . I like your using the 3D printer to make your part's !! I used to cut and weld my metal parts from metal that I had in my shop! KEEP IT COMEING !! Also your vacuum will change as the material you suck up increase's ! The more you HOG material, the vacuum will drop and you end up with plugging your hose with cobble / sand and you don't want that!! Learn to let the dredge suck the material to your nozzle and by all means USE A BLASTER HOSE to help free up that material ! My good friend John "Hoser" Oates made me a firm believer in the blaster hose ! I haven't heard from John lately , anybody heard from him

What kind of numbers, from what size of dredge, were you getting?

 

[LeeOregon]

All electric motors, including electric motors for a pump, have a maximum amp draw rating, which is the amperage when the motor is running. However, the problem you are running into pertains to the "inrush current", which is the amount of power required to get the motor spinning. On high efficiency motors, it can be as low as 1.5X the rated hp. For most, it is around 3X. In your situation, you are pulling a total of 20 amps for both motors once they are running, but to get them started, they need upwards of 60 amps.

I ran into the same problem building a portable conveyor powered by a gen. The solution was to use a three phase motor, wired to a variable frequency drive that uses single phase 120v on the input side, three phase on the output. Very efficient and it worked great. However, be sure to use an inverter gen because VFDs do not tolerate the high harmonics from normal generators.

Whatever you do, install at least two separate fuses/circuit breakers rated slightly above 10 amps, with a high inrush current (Fuse or breaker designed for motors). If your pontoon flips or sinks, they will trip and prevent you from being electrocuted.

Thanks Phil. I understood most of this beforehand, but the confusion comes from these 1hp pumps never getting below 10 amps.

 

[Phil]

A 1hp single phase motor on 120v will draw upwards of 16 amps. If you are around 10 amps, that is actually really efficient.

 

[LeeOregon]

I guess I shall count my blessing then. In that case I am eyeballing the WEN GN400i generator.
https://www.amazon.com/WEN-GN400i-4000-Watt-Generator-Compliant/dp/B07XZVLC9H

Its an inverter gen, 3500 running watts, 4000 starting. Its a bit wider than my current generator but smaller in both the length and height. It weighs a bit more too. Do you think this would be able to start my pumps, one at a time?

My only issue with the GN400i is that I would have to get the open frame option. I cant afford the closed, sound insulated one.

 

[Jason in Enid]

I recommend that you not waste time and energy re-inventing the wheel. Buy pre-existing dredge components that are proven to work, then figure out how to get your system supplied with water / air.

 

[Phil]

I guess I shall count my blessing then. In that case I am eyeballing the WEN GN400i generator.
https://www.amazon.com/WEN-GN400i-4000-Watt-Generator-Compliant/dp/B07XZVLC9H

Its an inverter gen, 3500 running watts, 4000 starting. Its a bit wider than my current generator but smaller in both the length and height. It weighs a bit more too. Do you think this would be able to start my pumps, one at a time?

My only issue with the GN400i is that I would have to get the open frame option. I cant afford the closed, sound insulated one.

I would measure the inrush current for both pumps first so you know exactly what size gen to buy. You will need a quality clamp on meter, or take it to an electrician or motor rebuild shop.

 

[LeeOregon]

I would measure the inrush current for both pumps first so you know exactly what size gen to buy. You will need a quality clamp on meter, or take it to an electrician or motor rebuild shop.

Does the fact that they are able to both run off a single 15 amp household circuit breaker for awhile give me any kind of ballpark?

 

[Phil]

Does the fact that they are able to both run off a single 15 amp household circuit breaker for awhile give me any kind of ballpark?

No. Inrush current happens in milliseconds and household circuit breakers are designed to allow for that without tripping (Dishwasher pumps, etc).

 

[LeeOregon]

To help take some of that instant initial load off the generator, would adding a good chunk of capacitance to the generator help? Let the caps charge, then plug in the pump, is what I was thinking

 

[russau]

What kind of numbers, from what size of dredge, were you getting?

I had a 4 inch dredge with a 6.5 HP Honda engine with a P180 Keene pump. and every setup on different dredge /engine / pumps would be slightly different . But just write down your best vacuum you reach and go from there . I don't remember what my #s were on my vacuum gauge. It's what you get that count's !

 

[Phil]

I know it is possible, but have never done it myself.

Give me a few to research something and I will post again later.

 

[Phil]

What are the specs on the 1hp well pumps you are using?

 

[LeeOregon]

What are the specs on the 1hp well pumps you are using?

https://www.amazon.com/gp/product/B00NTT2JO4/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1

 

[LeeOregon]

Well, I go to put the order in for the generator I want; its sold out everywhere, and I missed out on the apparently last one on amazon. Lol

 

[russau]

Before I'd order a well pump , I'd contact the manufacture to check on it's PSI out put to see if it's going to do the job your needing it to do ! The product info sheet info you listed didn't show any PSI rating and I don't remember any well pump putting out the PSI you'll need to get the suction you're looking for . It has the head pressure but....... I'm posting this just so you know what to expect with this well pump. Good Luck I hope it works for you.

 

[Reed Lukens]

Why a well pump? You get more out of a bilge pump... and you just need a battery...
https://www.amazon.com/Johnson-Pump...son+4000+gph+bilge+pump&qid=1595949255&sr=8-2

 

[Jason in Enid]

whoa now, do WHAT?! a 1HP well pump?! Do you have any idea the current draw? Most of them 250V to begin with, and if its a 120 its going to have a crazy amp draw. Secondly, I dont care how good of a well pump, its NOT going to power a dredge. I have a 3/4HP pump in my well, 50 foot down and the pressure and flow from it are CRAZY, but only when compared to a normal city pressure faucet. Once you try to make that into a dredge supply its going to fail miserably. You need both pressure AND volume for the suction hose and this just wont work like you want. Sucking flow sand and pea gravel is meaningless if you are trying to work a gold deposit.

 

[Phil]

A typical 3" dredge pump produces around 150 GPM at 70 PSI, whereas each well pump you have is producing 33 GPM at 90 PSI. With two pumps, you have 66 GPM and 180 PSI.

The Infinity Jet is far more efficient, and with the pumps submerged you gain even more efficiency. The only question is if you can design the system to compensate for the lower GPM using PSI? The river is providing all the water you need, and you have 180 PSI to work with, so yes........I think it is possible to make the well pumps work.

 

[Jason in Enid]

A typical 3" dredge pump produces around 150 GPM at 70 PSI, whereas each well pump you have is producing 33 GPM at 90 PSI. With two pumps, you have 66 GPM and 180 PSI.

The Infinity Jet is far more efficient, and with the pumps submerged you gain even more efficiency. The only question is if you can design the system to compensate for the lower GPM using PSI? The river is providing all the water you need, and you have 180 PSI to work with, so yes........I think it is possible to make the well pumps work.

Incorrect. You can not run well pumps in series. Running 2 pumps will give you 66 gallons, but the max PSI will not change. As an FYI, on pumps made to run in series, you do not double the volume. 2 pumps can be run in series to give higher pressure, or in parallel for higher volume, but not both.