Unknown motor/generator

Thread Starter

John11

Joined Feb 12, 2020
2
Hi folks
I bought this item on eBay where it was described as a generator and pump among a number of other descriptors.
It is principally sold as a mains water generator that will put out 5V when connected to a running tap.
It is close-coupled to a crude pelton wheel that is only obvious when the cover is removed.
I assumed that if I applied 5V to the leads, it would motor, but it doesn't.
Could someone tell me what they think this motor is and is there any simple way to make it run?
Also, what is the small board doing?
 

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dendad

Joined Feb 20, 2016
3,939
It looks like a generator to me, not a motor.
The coils are connected to a 3 phase bridge rectifier, capacitor and maybe a zener to prevent over volts.
It will not run as a motor.
 

MaxHeadRoom

Joined Jul 18, 2013
23,933
Agree, a 3ph generator, there must be a P.M. in the rotor, it could be ran as a 3 phase motor but would need a suitable commutation driver, similar to RC outrunner motors.
Not the way it is right now.
Max.
 

Dodgydave

Joined Jun 22, 2012
10,088
Like you said it's a 3 phase generator with bridge rectifier and smoothing capacitors...run it under the tap and measure the voltage...
 

Rich2

Joined Mar 3, 2014
190
Is it from a water meter?
Ours sends the water reading in to the water company wirelessly but it has no power supply
 

shortbus

Joined Sep 30, 2009
8,966
Looks like what my old water softener used to determine when to recharge. It measured the flow through the softener instead of a timer. Was supposed to make the salt last longer.
 

vu2nan

Joined Sep 11, 2014
189
Hi John,

Had it been a 5 V brush DC generator, it would have worked as a DC motor, on application of 5 V DC, .

But it's a 3 phase alternator, with a permanent magnet rotor, feeding a 3 phase bridge rectifier to obtain the 5 V DC output.

However, it would work as a motor should the rectifier board be replaced by a brushless DC motor driver.

Regards,

Nandu.
 

MisterBill2

Joined Jan 23, 2018
9,846
What you have is an ALTERNATOR with external rectifier diodes. It is not possible to make it motor by feeding a DC voltage anywhere. It is a cute device and it may work for charging a cell phone battery, but it is not a very high powered device.
 

Thread Starter

John11

Joined Feb 12, 2020
2
Thanks for the informative responses, folks, I wonder if someone could draw me or show me a schematic of the alternator, don't worry about the board.
It's not from a water meter, probably just a gimmick, like the radial engine that had magnets reciprocating in radially arranged coils, a distributor and all magnets connected to a conrod turning a shaft. Very cute but apparently atrociously inefficient. The video showed a speeded up manufacture of this gimmick on a small lathe.

Unfortunately, I happen to have a few brushed DC motor speed controllers.
So if'n I wants this thing to pump, I should find a small brushless controller.

What I am doing is building a model of a "perfect" British canal boat.
If I were 50 years younger, I would move to England and build me a full sized boat to live on.
I want it to be aquajet powered so I need some sort of pump amidships. I've seen these tiny motors around 1/4" diameter
called micro coreless motors which I could mount inside a pipe from stem to stern and attach a propeller.
Unfortunately, they run at very high rpm, so perhaps a geared version. What would these tiny coreless motors perform at slower speeds. I guess "suck it and see" is the apt maxim.
 

Alec_t

Joined Sep 17, 2013
12,317
What I am doing is building a model of a "perfect" British canal boat.
........
I want it to be aquajet powered
AFAIK, no British canal boats are aquajet powered, perhaps because of problems with weed and debris?
A small geared motor would be better than one of those tiny coreless ones. How will you waterproof it?
 

vu2nan

Joined Sep 11, 2014
189
Hi John,

Here's a 3-phase alternator schematic.

unnamed.jpg

Star connection is shown with the other option being delta.

Regards,

Nandu.
 
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MrSoftware

Joined Oct 29, 2013
2,015
These days if you can think it, someone has probably made it and it's for sale. There are a number of proper boat jet drives for RC toys for sale, google is your friend. Here's one example, I don't know if these are good or not, but you get the idea:

https://www.offshoreelectrics.com/products.php?cat=Jet+Drives




My guess is you'll get better performance from something purpose built, than by trying to adapt something that was originally intended for a different purpose.
 
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