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Teh SPIK
were there any gears on the tredmill
Which of these motors is best?
- Thread starter weirdarmadillo
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weirdarmadillo
Redneck
I thought good motors were more expensive than $50. Where would i find one of these?
And the treadmill
Motor is not ac, it's DC.
Jus out of curiousity, what does the armature do for the motor?
And the treadmill
Motor is not ac, it's DC.
Jus out of curiousity, what does the armature do for the motor?
Were did that idea come from?
The power a motor draws is mostly depended on the load put on the motor.
I have a gokart that cruises drawing about 40 amps, but from a
stop if I floor it the current goes over 250 amps, because the motor is working hard to get the weight moving.
My gokart takes about 2000 watts to go 35 or 40 mph, it is
a little heavy carrying me, 160 lbs and 4 car batteries.
Mike
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weirdarmadillo
Redneck
I calculated that since that motor has a 21.4 amp rating, if it's running at 95vdc it's at about 2000 watts. At 48vdc, about 1000 watts.
Sounds like it would work fine running on 48volts.
Since the motor says 21.4 amps, does that mean I have to supply at least 21 amps to have enough torque?
With proper gearing, what speed can I expect if it's hauling 150lbs + 4 car batteries? For how long?
Sounds like it would work fine running on 48volts.
Since the motor says 21.4 amps, does that mean I have to supply at least 21 amps to have enough torque?
With proper gearing, what speed can I expect if it's hauling 150lbs + 4 car batteries? For how long?
weirdarmadillo
Redneck
And what aH battery should i use?
How would the treadmill motor compare to a 24VDC 450W MOTOR by currie tech?
Keep in mind that the electric motor is (hopefully) the secondary mode of drive for events etc, gas being first.
How would the treadmill motor compare to a 24VDC 450W MOTOR by currie tech?
Keep in mind that the electric motor is (hopefully) the secondary mode of drive for events etc, gas being first.
truesprocket
Central Canadian
400watt DC to AC power inverter
this thing says in converts 12vdc to 145vdc & then chainges it to 115vac to two 115vac, 60Hz outlets, so can I make 145vdc out before it changes to ac ? I want to know if I can use this as a, or part of a dc motor controller & if not can I bridge the 2 115vac outlets to get more power for say a furnace blower motor
this thing says in converts 12vdc to 145vdc & then chainges it to 115vac to two 115vac, 60Hz outlets, so can I make 145vdc out before it changes to ac ? I want to know if I can use this as a, or part of a dc motor controller & if not can I bridge the 2 115vac outlets to get more power for say a furnace blower motor
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The math works out that if you run this 95 volt motor on 48 volts the power is about 25% or around 500 watts.
If you lower the voltage the current will be lower.
So in order to calculate the actual power we need to find the R or resistance of the motor. If we use ohms law V = I x R and rearrange it to V/I = R then 95Volts/21.4amps= 4.44 ohms.
The formula for Power in watts is Vsqrd/R or
48v x 48v / 4.44ohms = 519 watts
At full voltage 95v x 95v / 4.44 = 2033 watts
V = volts, I = current, R = resistance in ohms.
Mike
Your math for Ohm's law for solving resistance is correct, but it has flawed data for current. Specifically, the 21.4 amps is not the stall current. You have to take into account the motor's back EMF when it is turning. He would have to lock down the shaft and apply low voltage to the motor then read the current that flows to the motor and measure the voltage at the motor terminals to get as accurate a result as possible.
Seventy-nine dollars can get you this motor which has better RPM's, which allows for more gearing flexibility.
Hi HelloYOU,
I agree with your statement, so it seems if the motor is run at
a lower voltage the back emf is lower which would cause more current to flow, but, there is also less voltage to push the current against the lower back EMF. Is there anyway to get a better estimate of power other than between 25% and 50%?
Mike
PS This all seems to get complicated without the data, as you suggested. I have a 2 HP, 28 volt, 65 amp motor I run at 48 volts on a gokart. It cruises at about 40 amps, but if I floor it from a stop the current goes over 250 amps. That's 12,000 watts or about 16 hp, so for a short time that 2 hp is working its tail off. The current goes down as the motor speeds up(more back EMF).
Here's my video, I have since got new batteries and a beefier
motor mount that holds up better under all the torque.
http://www.youtube.com/watch?v=5MKjbXltAew
From the video it appears you are using a series-wound DC motor which is hard to get the motor data for with formulas other than the resistance data since their torque curves are exponential instead of linear like PM brushed motors. However, if you can get the torque curve data by dyno that can measure at very low speeds or motor manufacturer, then you can apply a ratio, in that at higher voltages the motor torque curve simply shifts up. In other words if you were to graph motor torque for various voltages you will notice that at higher voltages the curve has shifted some X amount. So if your motor is developing say 10 Ft*Lbs at 2400 RPM when ran at 36 volts, then at 72 volts if the same torque amount is required, then the new RPM will be 4800 RPM. From this you can also calculate the HP curve for the new voltage.
Ya, It was more a general question than specifically about my motor. I have a bit of an odd setup. I came across a free separately excited field motor. But my motor controller is for a series wound motor. I just fixed the field current and drive the armature with the motor controller. I don't know what effect
I would get if I started varying the field current. It works good now and I want to keep all the smoke in the parts.
Mike
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