# 200hp industrial control box



## ICEICEbaybee (Jan 28, 2017)

Found this while trying to figure out how oil companies control the motors on pump jacks. Seemingly, this technology is pricey to a regular citizen. So, this is full off - full on. Could a variable speed controller be added into this? Where?

https://goo.gl/images/18RR3L


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## brian_ (Feb 7, 2017)

That's just a set of contactors (relays). An EV doesn't need 3-phase contactors, because it has contactors to shut off the DC from the battery, and there's no need to have contactors in addition to the inverter on the AC side.

Yes, a variable speed control could be added, just as any EV with an AC motor has a controller/inverter. Since this motor is powered by an AC source (rather than a battery), the equivalent is normally called a variable frequency drive (VFD), rather than an inverter. If you think those contactors are expensive, go shopping for a VFD...


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## ICEICEbaybee (Jan 28, 2017)

brian_ said:


> That's just a set of contactors (relays). An EV doesn't need 3-phase contactors, because it has contactors to shut off the DC from the battery, and there's no need to have contactors in addition to the inverter on the AC side.
> 
> Yes, a variable speed control could be added, just as any EV with an AC motor has a controller/inverter. Since this motor is powered by an AC source (rather than a battery), the equivalent is normally called a variable frequency drive (VFD), rather than an inverter. If you think those contactors are expensive, go shopping for a VFD...


Thanks for the clarification. 
I bought a fisker karma motor some time ago. Rating is 200hp. I have some questions if you don't mind...

Are all AC motors the same or can they be built to operate under a specific sine wave? 
I'm trying to learn in my old age and may not have the correct terminology down. I found the fisker karma inverter for this motor but I imagine the controller would be closed source software / firmware? 
Can I possibly mix and match components to make the motor spin?
Thanks in advance.


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## ICEICEbaybee (Jan 28, 2017)

Disregard. Found out the difference in another post. Asynchronous and synchronous are where they differentiate. Looks like this is a synchronous type.


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## brian_ (Feb 7, 2017)

ICEICEbaybee said:


> Found out the difference in another post. Asynchronous and synchronous are where they differentiate. Looks like this is a synchronous type.


The industrial motor will be an induction motor, and thus asynchronous. The simple on/off control means that the motor must be able to start from zero speed with the supplied power at line frequency; for an induction motor this means huge slip (which can work), but for a synchronous motor it's just not workable.

In practice in an EV, there is always a controller/inverter that provides the right frequency (and with a synchronous motor, the right phase) of input power to the motor; starting from a standstill with huge slip wouldn't work acceptably even with an induction motor.


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## brian_ (Feb 7, 2017)

ICEICEbaybee said:


> I bought a fisker karma motor some time ago. Rating is 200hp. I have some questions if you don't mind...
> 
> Are all AC motors the same or can they be built to operate under a specific sine wave?


Any sine wave form is the same as any other, other than frequency and phase. The right frequency is determined by the rotational speed (plus the right amount of slip for the load in the case of induction motor), and the phase must match the shaft rotational position of the motor in the case of a synchronous motor. This means that in theory any inverter can run any motor if the voltage and current capacity are adequate, and you can control the frequency and phase to match the motor's requirements.



ICEICEbaybee said:


> I found the fisker karma inverter for this motor but I imagine the controller would be closed source software / firmware?
> Can I possibly mix and match components to make the motor spin?


Yes, typically production EV controllers/inverters are not easy to adapt to a different motor than the one for which they are factory-programmed, or to control with anything other than the original car's systems. Some mixing and matching has been done, typically by replacing the controller portion of the electronics with something that can be programmed as required.


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