Motor Experts,

Could someone tell me where I could buy a small electric motor that
will run off 300V DC? It could be either brushless or with brushes,
one hp. RPM could be 2,000 to 8000 rpm.

I'm with a small company that is making our first electric car. We
have a 2001 Honda Civic, have removed the gas motor and will be
putting in an AC motor, controller, lithium-ion batteries and other
electronics.

We need a DC motor to run the air conditioner. Our battery pack is 96
cells at 3.2 V each, so our battery pack will be 308 V. We have to
have high voltage, in order to provide enough power to the AC motor.
We can't run it off 12V, because it would take too much current from
our DC/DC converter.

Does anyone know a company or a brand that sells a small, electric,
off-the-shelf, DC motor, along with the controller, that is powered by
300V DC? Is such a thing available?

Thank you,
Bill
eeVee Motors

 

A standard VFD unit with a single phase 208 -240 AC input would work in your situation. Then all you would need is a standard three phase motor with the common 208 - 230 / 460 volt input ratings.
Check out eBay. I have bought several of them with a 200 -240 volt AC single phase input and up to 3 hp output capacity. Most of them convert the AC into DC and everything internal is driven off the internal line sourced DC system. Setting one up to use a DC input is simple.
A good used unit goes for around $50 - $100.
Plus you would have your speed, reversing, and often regenerative breaking capabilities all ready built in. One potentiometer and one switch for speed and direction control.

__________________
"Issue a general safety warning. Then look the other way and allow stupidity the chance to eliminate itself." -- tcmtech
"Those who can, Will. Those who can't, will achieve positions of power over those who can and then promptly stop them." -- tcmtech
"Your impossibility may just be my day to day routine." -- tcmtech

 

The last time I saw a 300V DC motor it was driving the ball screw on the 7-ton spindle of a machine tool. Small and cheap don't seem to go hand in hand with such a motor.

__________________
We never have time to do it right; but we always have time to do it over.

 

TMC Tech,

Thank you very much for giving me this answer. However, I don't completely understand it. Would you be willing to help me understand it better?

The VFD is the controller, right? (not the motor)

The specs for a VFD says it works for 208 to 240 AC input. However, you are saying that you can actually connect DC voltage to a VFD? I can connect 300 V DC to a VFD controller (with specs that say AC) and it will work? Am I describing that correctly?

Then I would buy an AC motor, 3 phase (208/230/460 AC input) and use the VFD to control the AC motor.

Am i describing that correctly?

For my usage, i would like to buy a new motor and new VFD controller. Do you have a suggestion for brand name and/or company where I could buy a new motor and VFD controller?

thank you very much for your help,
Bill

 

VFD stands for Variable Frequency Drive. Just do an on-line search for dealers. They are a common device. Same with a 3 phase motor.

Most VFD units take the single or three phase AC input and rectify it to DC. All of the internal power is derived from that DC source. By just feeding DC into two of the three power input wires they will work normally off of a battery system.
However if you tie the battery into the DC side of the rectifiers the dynamic breaking functions can allow for a regenerative breaking effect also.

The DC input capacity is not usually referred to on the manufacturers specs sheets though.

Here are the manuals for three units I have worked with that were able to be set up for DC input without modifications.

Attached Files

	Fugi 2C9S Operators Manual.pdf (303.7 KB, 217 views)
	Hitach iVWE.pdf (1.81 MB, 135 views)
	Toshiba VFSX Manual.pdf (2.67 MB, 54 views)

__________________
"Issue a general safety warning. Then look the other way and allow stupidity the chance to eliminate itself." -- tcmtech
"Those who can, Will. Those who can't, will achieve positions of power over those who can and then promptly stop them." -- tcmtech
"Your impossibility may just be my day to day routine." -- tcmtech

 

I'm not saying Tcm is wrong it'll work I have Four controllers like what he is talking about there bigger then the motor LOL
I would like to no what dose that have to do with air conditioner It doesn't need any braking. What he talking about is not that easy to do. And your not going to find any motors in the 300 volt range
You would be better off tapping your supply at say 90 to 120 volts and using that for
a 90 to 120 volt Dc motor at 30 amps or less Look here
Baldordirect, your home for Baldor Motors & Drives : DC Motors
Sale Price $1,110.75 lol

__________________
Burt
http://mybe80be.com
http://stores.shop.ebay.com/mybe80be__W0QQ_armrsZ1

 

Sorry I missed the compressor drive system part. Regen not needed.

A 300 volt battery is very close to the rectified peak voltage of a 208 three phase line/ 208 x 1.414 = 294 volts.
Therefore a VFD running a 208 volt rated AC three phase motor gives him an off the shelf variable speed motor compatible with a 300 volt DC source.

He could also skip the motor to compressor connection and just use a stock three phase commercial air conditioner compressor. The cooling capacity of a car is very small (4000 - 8000 BTU) and an electrically driven compressor that small is about the size of a standard automotive compressor any way. Just use one thats rated for what ever type of freon your vehicle is going to be set up for. That would gain some added system efficiency as well!

__________________
"Issue a general safety warning. Then look the other way and allow stupidity the chance to eliminate itself." -- tcmtech
"Those who can, Will. Those who can't, will achieve positions of power over those who can and then promptly stop them." -- tcmtech
"Your impossibility may just be my day to day routine." -- tcmtech

 

That would have my vote. That would be easier to put together and way cheaper. And no loss with belts or hard to make adapters

__________________
Burt
http://mybe80be.com
http://stores.shop.ebay.com/mybe80be__W0QQ_armrsZ1

 

What's the maximum battery voltage?

Make sure it's under the AC voltage of the VFD ×√2, for example if it's rated to a maximum of 250V the maximum DC voltage you can power if off is 353V.

__________________

I do not answer private messages asking for help because no one else can: benefit from advice I may give or correct me if I'm wrong.

Please ask on the open forum if you have a question and I'll be happy to help, if I know the answer.

 

Baldor and other major motor mfrs have new DC motors -- Grainger also only up to 180V.
To save on some bucks you may have to go surplus.
http://www.tdigrp.com/products

You can as already said drive the compressor or whatever with another AC motor and another VFD.

OTHER QUESTIONS

The VFD is the controller, right? (not the motor)
REPLY Yes

The specs for a VFD says it works for 208 to 240 AC input. However, you are saying that you can actually connect DC voltage to a VFD? I can connect 300 V DC to a VFD controller (with specs that say AC) and it will work? Am I describing that correctly?
REPLY Yes you are basically correct the DC bus voltage is 1.4 x input AC ie 230 so about 325 VDC. The magic term in this application is DC bus share.

Then I would buy an AC motor, 3 phase (208/230/460 AC input) and use the VFD to control the AC motor.
REPLY Yes

For my usage, i would like to buy a new motor and new VFD controller. Do you have a suggestion for brand name and/or company where I could buy a new motor and VFD controller?
REPLY any name brand will do Allen Bradley Hitachi SJ 300 etc. I intend to retrofit a 56 Chev pickup with 50 HP 3 phase and will use Hitachi SJ 300

Dan Bentler
Seattle