Finding the Right Electric Motor for My Pump Setup

In summary, this individual needs expert knowledge on gearbox design/development in order to achieve the desired torque off of an electric motor. However, the power that is required is too high for the current supply.
  • #1
Possibilites
3
0
OK, here's my dilemma:

I have a pump that requires 3600RPM, 24lb.ft. of torque (optimally) to run it. It was attached to a gasoline powered 16HP motor, and I need it to run off of an electric motor now.

Not so difficult, you say?

My only power supply is limited to 24VDC.

I am looking for someone who has expert knowledge on gearbox design/development. It is unknown as to which 24VDC motor will be required to achieve the above 3600RPM, 24lb.ft. Torque, because the gear ratio(s)/gearbox has to be addressed first. It is working the equation in reverse, I know, but it's the only way apparently.

Please think your answers through!
Thanks for any help.
 
Last edited:
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  • #2
You do realize that to produce 16 hp (12 kW) of power, you need a current of 500 A with 24 VDC (not counting losses). No matter what motor you use or what gearbox you have, you will need that 500 A current; Which, according to http://en.wikipedia.org/wiki/American_wire_gauge#Table_of_AWG_wire_sizes", requires, at least, TWO 4/0 wires (but I'm no electrician).
 
Last edited by a moderator:
  • #3
Possibilites said:
OK, here's my dilemma:

I have a pump that requires 3600RPM, 24lb.ft. of torque (optimally) to run it. It was attached to a gasoline powered 16HP motor, and I need it to run off of an electric motor now.

Not so difficult, you say?

My only power supply is limited to 24VDC.

I am looking for someone who has expert knowledge on gearbox design/development. It is unknown as to which 24VDC motor will be required to achieve the above 3600RPM, 24lb.ft. Torque, because the gear ratio(s)/gearbox has to be addressed first. It is working the equation in reverse, I know, but it's the only way apparently.

Please think your answers through!
Thanks for any help.

The required power is:

[tex]
3600 \frac{1}{\mathrm{min}} \, \times \frac{1 \mathrm{min}}{60 \, \mathrm{s}} \times \frac{24 \mathrm{lb. \, ft.}} \times \frac{1 \, \mathrm{HP}}{550 \, \mathrm{lb. \, ft. \, s}^{-1}} = 2.62 \, \mathrm{HP} \times \frac{745.7 \, \matrm{W}}{1 \, \mathrm{HP}} = 1950 \, \mathrm{W}
[/tex]

which, on 24 V voltage would require a constant current of:

[tex]
1950/24 = 81.3 \, \mathrm{A}
[/tex]
 
  • #4
Dickfore said:
The required power is:

[tex]
3600 \frac{1}{\mathrm{min}} \, \times \frac{1 \mathrm{min}}{60 \, \mathrm{s}} \times \frac{24 \mathrm{lb. \, ft.}} \times \frac{1 \, \mathrm{HP}}{550 \, \mathrm{lb. \, ft. \, s}^{-1}} = 2.62 \, \mathrm{HP} \times \frac{745.7 \, \matrm{W}}{1 \, \mathrm{HP}} = 1950 \, \mathrm{W}
[/tex]

which, on 24 V voltage would require a constant current of:

[tex]
1950/24 = 81.3 \, \mathrm{A}
[/tex]

Actually, it is:

[tex]
3600 \frac{\mathrm{rev}}{\mathrm{min}} \, \times \frac{2 \pi \mathrm{rad}}{1 \, \mathrm{rev}} \times \frac{1 \mathrm{min}}{60 \, \mathrm{s}} \times 24 \mathrm{lb. \, ft.} \times \frac{1 \, \mathrm{HP}}{550 \, \mathrm{lb. \, ft. \, s}^{-1}} = 16.45 \, \mathrm{HP} \times \frac{745.7 \, \matrm{W}}{1 \, \mathrm{HP}} = 12 267 \, \mathrm{W}
[/tex]

which, on 24 V voltage would require a constant current of:

[tex]
12 267/24 = 511 \, \mathrm{A}
[/tex]
 
  • #5
Ahh, yes! The formula for power due to rotational motion is:

[tex]
P = \tau \omega
[/tex]

where [itex]\tau[/itex] is the torque and [itex]\omega = 2\pi f[/itex] is the angular velocity (circular frequency). I forgot the factor of [itex]2\pi[/itex] in my previous calculation.
 
  • #6
I see.
In other words, it is outside my capacity to establish that much amperage in the current situation, and I thank you for the information.

Perhaps another?
In general, I am curious as to what material makes up the internal rotational section of a generator head assembly (not the Cu wire, rather the "frame" it is mounted onto{stator assembly?})?
Cast Al?
Cast Fe?


Why was that particular material chosen for that item?
I am trying to determine whether it has anything to do with magnetic properties, eddy currents, or if it can be made of a hardened polymer and still function inside a generator head assembly as it's intended, instead of using the heavier metal(existing) counterpart?
 
  • #7
Cores of electric machines are not cast, but laminated, i.e. built of layers of ferromagnetic sheets (usually steel alloys which differ in magnetic properties depending on application) in order to avoid losses due to eddy currents.
 
  • #8
Thanks again for the useful input. I seem to be batting a very low average with some things i am trying to study.
 

1. How do I determine the correct size of electric motor for my pump setup?

The correct size of an electric motor for your pump setup depends on several factors, including the size and type of pump, the required flow rate and pressure, and the power source available. It is important to consult with a professional or refer to the manufacturer's specifications to determine the appropriate motor size for your specific pump setup.

2. Can I use any type of electric motor for my pump setup?

No, not all electric motors are suitable for pump setups. The type of motor needed will depend on the type of pump being used, such as submersible, centrifugal, or diaphragm. It is important to choose a motor that is compatible with your pump and its intended use.

3. How do I know if my pump setup requires a single-phase or three-phase electric motor?

The type of electric motor required for your pump setup will depend on the power source available. Single-phase motors are suitable for household or small-scale use, while three-phase motors are typically used for larger or industrial applications. It is important to consult with a professional or refer to the manufacturer's specifications to determine the appropriate type of motor for your specific pump setup.

4. Can I adjust the speed of my electric motor to control the flow rate of my pump?

Yes, the speed of an electric motor can be adjusted to control the flow rate of your pump. This can be achieved through the use of a variable frequency drive (VFD) or by selecting a motor with adjustable speed options. It is important to consult with a professional or refer to the manufacturer's specifications to determine the best method for controlling the speed of your motor for your specific pump setup.

5. How do I maintain my electric motor for optimal performance in my pump setup?

To maintain optimal performance of your electric motor in your pump setup, it is important to regularly inspect and clean the motor, ensure proper lubrication, and monitor for any signs of wear or damage. It is also recommended to follow the manufacturer's maintenance guidelines and have the motor serviced by a professional when necessary.

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