can u plz suggest me that if i want to replae a 7.5 bhp engine with a d.c. motor, then what is required volts of d.c.motor to equalize it(7.5 bhp engine).
Re: required volt for a d.c. motor to equlize with a 7.5 bhp engine
12/17/2008 2:21 PM
As motor horsepower increases, generally the voltage of the motor increases. There is no direct relationship between horsepower and voltage, it is a practical relationship that has to do with the wire size and current. Higher amperage means larger internal wiring in the motor, and external wiring feeding power to the motor.
1 hp equal 746 Watts. Watts Equal amps times Volts or P=IE. For example a 1 hp @ 10 V motor 746/10=74.6 Amps which would require the use of number 6 copper wire which is fairly large and expensive.
The same 1 hp could be obtained at 100 V 746/100=7.46 amps. Number 14 wire would easily carry 7.46 amps, and is much less expensive.
The real limiting concern is the practicality of conductor size when building a motor, my suggestion is to investigate the availability of motors in your horsepower range, by doing that you would determine what the industry standard is for voltage for the motors in that horsepower range.
BTW none of these figures include efficiency of the motor.
The motors will probably be available in a range of voltages, also it may be possible to reduce the horsepower of your motor to do the same job as an internal combustion engine, the manufacturer of the motor would be the best source of this information. If there's any doubt go with the larger horsepower electric motor, it is better to have extra capacity than not enough.
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Re: required volt for a d.c. motor to equlize with a 7.5 bhp engine
12/17/2008 2:39 PM
Just a footnote, my wire sizes are for copper wire in free air, and are the minimum size wire, and used for example only. You should have a professional determine your necessary wire size.
__________________
"The reasonable man adapts himself to the world; the unreasonable one persists in trying to adapt the world to himself. Therefore all progress depends on the unreasonable man" George Shaw
Re: required volt for a d.c. motor to equlize with a 7.5 bhp engine
12/17/2008 3:35 PM
There is no set voltage to obtain 7.5 hp other than the physical limits of the parts. The lower the supply voltage the greater the current the conductors have to handle for the same amount of work. So the lower voltage motor would be a bigger package
Here is a link to a catalog of electric motors used in the Material Handling Industry may help to get a idea what available.
Also if the motor that you are replacing is to replace a gas engine then you can reduce the hp by about a third.
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Motor Voltage for Engine
Re: required volt for a d.c. motor to equlize with a 7.5 bhp engine
