Will a 1/3 horse power sump pump motor burn up at half power?

[Weird Al/ Tony]

I am building my own battle bot and I'm working on running it off of two 12V batteries. It will be driven by two heavy sump pump motors. I will only be able to obtain a possible half power off of the batteries and I need to know if that will ruin the engines. I have been told it will by a freind but I dont beleive her. So I need some help. I dont want to waste/ruin the motors after all!

[Daniel_LaFleur]

Originally Posted by Weid Al/ Toni

I am building my own battle bot and I'm working on running it off of two 12V batteries. It will be driven by two heavy sump pump motors. I will only be able to obtain a possible half power off of the batteries and I need to know if that will ruin the engines. I have been told it will by a freind but I dont beleive her. So I need some help. I dont want to waste/ruin the motors after all!

OK, There's not quite enough info here but I'll give it a try.

By "only be able to obtain a possible half power off of the batteries" do you mean that the pump is 24V and you are running it at 12V? If so, then your friend is absolutely correct. The motor will try and do the same amount of work with only 1/2 the voltage thus requireing twice (roughly) the current. This will heat the motor more.

In addition, most sump pumps are designed to work submerged in water. They use the water to cool the motor, thus will need extra cooling if it is run using air to cool it.

[Stephen Kowski]

Originally Posted by Weid Al/ Toni

I am building my own battle bot and I'm working on running it off of two 12V batteries. It will be driven by two heavy sump pump motors. I will only be able to obtain a possible half power off of the batteries and I need to know if that will ruin the engines. I have been told it will by a freind but I dont beleive her. So I need some help. I dont want to waste/ruin the motors after all!

What are your loading conditions? Do you have a model number for the motor so that we might be able to better understand? Are you using the batteries that we used for competition or are these some other chemistry (NiCd, Li-ion)? are these batteries in series, parallel, or individually connected to the motors?

Why are you only able to obtain half power? How are you gearing this drive train? wheel size? wheel traction? In general, depending on the loading condition, the power your motor demands is not a static number

Will it burn up? Well that depends a lot on the motors thermal constants (casing, efficiency, etc) and it's ability to handle a stall current among other things

More information is required to give you a good answer.

[Weird Al/ Tony]

when I posted this I knew nothing about the topic I was asking about. so here arwe the facts. I have a 115 A/C volt motor, I'm using a 12 D/C volt battery to power it. the motor is 5.7 amps, 60 hz, 1725 RPM, and it is non submersible. air cooled and isnt ment to be wet. I have a model #: xqj48517028j p and I ndont know what the p means. it also says it is thermally protected, single phase. what is single phase? and it is 60 cycle? what is that. fla= 5.8 sf= 1.0 and I have no clue what any of that means. help me out, thanks.

[kevin.li.rit]

Originally Posted by Weid Al/ Toni

when I posted this I knew nothing about the topic I was asking about. so here arwe the facts. I have a 115 A/C volt motor, I'm using a 12 D/C volt battery to power it. the motor is 5.7 amps, 60 hz, 1725 RPM, and it is non submersible. air cooled and isnt ment to be wet. I have a model #: xqj48517028j p and I ndont know what the p means. it also says it is thermally protected, single phase. what is single phase? and it is 60 cycle? what is that. fla= 5.8 sf= 1.0 and I have no clue what any of that means. help me out, thanks.

My guess is that you won't be able to run it directly off the 12 bolt battery. It sounds like it uses the 110 volts out of your wall which is single phase. I.E. there is only one sinusoidal wave coming out of your standard wall outlet. (opposed to 3 sinusoids in 3 phased 220 volts). 60 cycle refers to the 60 hz which is the frequency of the sinusoid in your wall.

The thermal protection most likely means that the motor will stop running if it gets to hot to prevent it from damaging itself.

[Weird Al/ Tony]

well what are sinusoids. and it is a wall plug type motor. so that means like even if I wanted to I couldnt convert it? and what about like wheelchair motors cause I got those. and I mean what if I used like a fan motor from a like normal around the house use post fan or whatever? would i not be able to use that with a battery.

[kevin.li.rit]

Originally Posted by Weid Al/ Toni

well what are sinusoids. and it is a wall plug type motor. so that means like even if I wanted to I couldnt convert it? and what about like wheelchair motors cause I got those. and I mean what if I used like a fan motor from a like normal around the house use post fan or whatever? would i not be able to use that with a battery.

Sinusoid are sine waves. You would need an inverter to go from the DC of the battery to AC but most inverters do not produce a true sine wave. A regular house fan is mostly likely an AC motor; all mine are. You could maybe use a fan motor off your PC which is a DC motor.

The wheel chair motors are mostly likely DC so they could be usable.

Wikipedia has good info on AC and DC

[Weird Al/ Tony]

alright thanks. ya see I'm trying to get a powerful motor that will be hard to stop while it is receiving power. that way it will be able to power my robot through all opposition. (this robot is for like a hobby, not the competitions) and I'm thinking that I have some older wheelchair motors, and other stuff. but they arent very fast and they dont have much power. I'd probably need either a gear box or some good belts to allow diffrent speed and torgue. I kinda think I know what i'm talking about. I mean I'm just getting on a team so I dont have alot of robotics experience.

[kevin.li.rit]

Originally Posted by Weid Al/ Toni

alright thanks. ya see I'm trying to get a powerful motor that will be hard to stop while it is receiving power. that way it will be able to power my robot through all opposition. (this robot is for like a hobby, not the competitions) and I'm thinking that I have some older wheelchair motors, and other stuff. but they arent very fast and they dont have much power. I'd probably need either a gear box or some good belts to allow diffrent speed and torgue. I kinda think I know what i'm talking about. I mean I'm just getting on a team so I dont have alot of robotics experience.

Go FIRST Retro and use some 12 Volt Drill Motors. They'll come with gearboxes with high low speeds too! Judging by your team number your team might still have some.

[EricH]

I think that you may want to talk to your local physics teacher. At the least, he can help you through some of the concepts and the math behind them.

I'll give a brief rundown of some of them.

Voltage: difference in electrical potential energy between two points.
Amperage or current: how fast that electrical energy can move.

Power (or energy): force*distance.
Work: power/time.
Torque: force * distance, usually referenced with regard to rotational motion. You'll want to know this eventually.

Gearboxes multiply and divide torque and rotational speed, which translates via wheels to linear power and linear speed.

BTW, you may want to look up some of John V-Neun's whitepapers. I think that those will help you with some of the math that is behind the design of a drivetrain, and quite possibly help you optimize the drive for the motors you have.

[Ether]

Originally Posted by EricH

Power (or energy): force*distance.

power and energy are not the same thing.

Originally Posted by EricH

Work: power/time.

you have that backwards.

power = work/time

Originally Posted by EricH

Gearboxes multiply and divide torque and rotational speed, which translates via wheels to linear power and linear speed.

torque translates to linear force, not linear power.


~

[EricH]

Originally Posted by Ether

power and energy are not the same thing.

They aren't, but for some reason known to nobody, they share the same units. Joules in the SI, BTU and its equivalents in the Eng. system. (Eng. == either English or Engineering, which for functional purposes are indistinguishable.) This makes the calculations very similar when all's said and done.

150 kJ << without my telling you, is this power or energy?

150 kN-m << That's power, but to get that I had to expand the unit. Also note that that is a torque unit as well.

Energy has a number of ways to get to the kJ unit, none of them simple. Something about energy/mass * mass in a number of weird combinations makes it a little hard to translate out of handwriting.

[Ian Curtis]

Power is measured in Watts. Energy is measured in Joules.

Work and Energy have the same units. Power and Energy do not. Think about it, to find power Power you take the derivative of work with respect to time. This will divide the units of work by time.

[kevin.li.rit]

Originally Posted by EricH

150 kJ << without my telling you, is this power or energy?

Well thats energy because power would be j/s.

And I don't think its torque because you're not taking the cross product

[Al Skierkiewicz]

Al,
It not a simple matter of voltage in this case. A motor turns by using magnetic fields. In DC motors, the fields are generated via permanent magnets in the case and the current through the windings. In AC motors, there is generally no magnets and no brushes. The magnetic fields are generated by the AC current flowing through the motor windings and the induced currents that flow in other structures in the motor. Connecting this sump motor to a DC battery would cause it to heat up over time but it would never move.