# Good deals on AC motors and VFDs?



## PStechPaul (May 1, 2012)

I happened upon a post on another forum which had a link to a 1 HP 120 VAC single phase to 220 VAC three phase WX/TECO VFD, and a 1/3 HP 3 phase motor, for just $155. 
http://dealerselectric.com/item.asp?PID=6897

They also have some good prices on other items, such as:
http://dealerselectric.com/item.asp?cID=111&PID=8635 (6HP 200V 1800 RPM Marathon ODP $200)
http://dealerselectric.com/item.asp?cID=111&PID=8363 (1.5 HP 200V 1200 RPM Marathon ODP $120)
http://dealerselectric.com/item.asp?cID=0&PID=4581 (1 HP VFD, 115V single phase input, 220 VAC 3 phase output, $115)

I don't know just how they are getting 220 VAC output from 115 VAC input, but they must have some sort of voltage booster built-in. I'm thinking if it is boosted from the raw filtered AC input to DC link, it may be 140-160 VDC, and thus suitable for a moderate size battery pack. I have requested additional information. If this is the case, these may be suitable for small EVs such as bikes, quads, and lawn tractors.

Upon closer inspection of the user manuals, I see that the EV series VFD operate from 190-400 VDC, and the Fluxmaster is 200-410 VDC. So, it probably has a voltage doubler input circuit to provide the DC link voltage. It is possible to chop the DC voltage from a battery pack to double the voltage, but probably not the best method.

Also, the 200V motors may be more suitable than their 220/440 VAC cousins for overclocking to get higher HP. But the ODP construction may not be as well suited to an EV, especially something like a tractor which may be used in all kinds of weather, and not offer as much protection as a car.

This seems to be a surplus shop only a couple hours north from me in NJ, so it might even be worth a visit.


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## major (Apr 4, 2008)

PStechPaul said:


> I don't know just how they are getting 220 VAC output from 115 VAC input,


They're not. It is a mistake on the add. See: http://www.twmi.com/products/controls/drives/JNEV/JNEV-101-H1


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## PStechPaul (May 1, 2012)

Here are the specifications from the user manual:










Here is the spec sheet for the other drive:


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## PStechPaul (May 1, 2012)

BTW, I did a simulation on a possible means to convert 140 VDC (rectified 120 VAC) to 280 VDC, using a half-bridge, two 20 uF capacitors, and two rectifier diodes. Input power is 652W, output power is 614W, for an efficiency of 94%. Frequency is 25 kHz. C3 carries 5.6 amps, 3.5 amps through C5. Peak current is less than 14 amps.


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## PStechPaul (May 1, 2012)

Here is another simulation, but with a simple voltage doubler at 60 Hz. It requires 1400 uF capacitors, and an optional LC output filter. It provides 810 watts with input of 859 watts for efficiency of 94%:


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## major (Apr 4, 2008)

I wonder why the specification document list output at 100 - 120V.










It appears to be courtesy of the manufacturer. 120V three phase motors are not common if available at all. There are a number of references to this model stating 230V output with 120V input. It appears to have been around for a while; I saw reference dated 2008. 

I've run 230V 3ph drives on 120V 1ph using a voltage doubler, but just at no load. No big deal deal there. And these are only rated to 1 hp, so maybe they are doing it. But relevance to EV drives? I don't think so. Well, maybe little 1 hp EVs.


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