Very strong and very small electric motor

[peranders]

I'm searching for this:

230 VAC and 3 x 400 VAC (maybe more), 50-60 Hz
Up to 4 kW but less for the single phase version
I need 1.7-1.8 kW to the load
Good efficiency
Small, cola can size or in that region.
IP67 water proof
Ex environment (really harsh environment)
Can be water cooled since I have running water
Rotation speed 3000-6000 rpm not a problem but the end speed is 6-10 rpm via a gear box
Speed control of the motor but only a soft start than max speed for 5-10 minutes.

I haven't got a clue which type of motor I should look for but I'll guess something for 300-500 V internally and no brushes since the service interval should be long.

Ping motor experts!

[Geek]

Do surplus torpedo motors run on electricity or compressed air?

4KW with 1.8KW to the load = 2.2KW as heat... in a cola can size, it'll probably go *BOOM!*

Cheers!

[peranders]

1.8 kW is the very minimum.

[Speedskater]

In the recent past, some US collages and a competition of racing electric open wheel cars (that raced in conjunction with CART races). The one I saw started with a stock 3 phase AC, 60Hz 30hp motor. They oil cooled it and increased the drive frequency to maybe 200 or 300HZ I think that this resulted in a final 300hp. A web search may find more details.

[star882]

There was some discussion about using industrial electric motors for EVs. Industrial motors are built many times tougher than design specifications, which gives lots of room for "overclocking". Especially for peak power which is what defines the "feel" of the performance. If a 10x overclock is typical, that means a 10HP motor would be sufficient for a more "everyday" EV with a peak requirement of 100HP. Since hypermilers generally do not need much performance and aerodynamic modifications reduce continuous power requirements, even smaller motors can be used.

I have read about some hybrid bicycle builders modifying old alternators into powerful motor/generators. They would replace the field coil with some powerful magnets (often out of old hard drives and microwave ovens) and replace the rectifier with an inverter. Apparently, a typical alternator is good for some 10kW peak!

[insta]

1.8kW is only about 2 horsepower. He isn't asking for something completely unreasonable.

[ashevillebob]

The US carwash industry probably makes the motor you need that is otherwise used for pumping soap or water or rotating wheel scrubber brushes. These motors are usually water proof or water resistant and very low or no maintenance. KleenRite Corp. has a website I order from regularly for my carwash. I use a soap booster (Blue/White brand) pump motor that is about the size you are looking for. After winter tempertures require us to air purge the lines between customers, it shoots a soap/water mixure 30 ft in 3 seconds through 1/4 tubing so it's gotta be pretty stout.

[Andrew Eckhardt]

Originally Posted by insta

1.8kW is only about 2 horsepower. He isn't asking for something completely unreasonable.

2 horsepower can be had in a soda can size but not without proper forced air or liquid cooling and probably a rotor speed quite a bit higher than 6000 RPM. If you can go to 30 or 40k RPM ot gets easier, maybe even common. A properly cooled series wound universal or PMDC motor can acheive that sort of power density.

[Andrew Eckhardt]

Originally Posted by peranders

I'm searching for this:

230 VAC and 3 x 400 VAC (maybe more), 50-60 Hz
Up to 4 kW but less for the single phase version
I need 1.7-1.8 kW to the load
Good efficiency
Small, cola can size or in that region.
IP67 water proof
Ex environment (really harsh environment)
Can be water cooled since I have running water
Rotation speed 3000-6000 rpm not a problem but the end speed is 6-10 rpm via a gear box
Speed control of the motor but only a soft start than max speed for 5-10 minutes.

I haven't got a clue which type of motor I should look for but I'll guess something for 300-500 V internally and no brushes since the service interval should be long.

Ping motor experts!

The only way you're going to get that kind of power density is to rectify and switch (or otherwise commutate) at much higher frequencies. There's not so much of a problem with brushes, particularly with intermittent duty. Brushes are very reliable. I'd think about starting with an angle grinder motor, something of that type.

[GK]

Originally Posted by peranders

I'm searching for this:

230 VAC and 3 x 400 VAC (maybe more), 50-60 Hz
Up to 4 kW but less for the single phase version
I need 1.7-1.8 kW to the load
Good efficiency
Small, cola can size or in that region.
IP67 water proof
Ex environment (really harsh environment)
Can be water cooled since I have running water
Rotation speed 3000-6000 rpm not a problem but the end speed is 6-10 rpm via a gear box
Speed control of the motor but only a soft start than max speed for 5-10 minutes.

I haven't got a clue which type of motor I should look for but I'll guess something for 300-500 V internally and no brushes since the service interval should be long.

Ping motor experts!

Look up bore water pumps. These are water-cooled, typically 3-phase and designed to fit into bore holes and very compact (thanks to the water cooling).
The last one I had a look at on the job was about 1.5m long (including the pump bit), 200mm in diameter and rated at 50kW. Of course there are smaller ones.

Edit:
Like this: http://www.cheapapumps.com.au/three_...ore_pumps.html
Single phase motors: http://www.cheapapumps.com.au/single...le_motors.html

These are specified to fit down a 4" minimum diameter casing and are a loose(ish) fit. Probably 70mm-80mm in diameter.
Not quite coke can size, but about as small as it's going to get.