I Need Help In Understanding Electric Motor Dynamometer Testing AC and DC

OK extremely long time reader but first time poster. I need some help understanding dynamometer for electric motors. I would like to test motors under load up to 5HP. I have several motors and I would like to use a selected motor as the generator load. I understand this is a very broad question but I have to start somewhere.   What are some things I might need? Here are some things I have. Motor speed controller  Motor torque controller Electric motors off all sizes 1/3 to 20HP Some have a brake installed. Would I need to use a motor with a brake and apply the brake as the load? I don't want to use water or any fluids as a braking system. Also regenerative would be great also. I thank you for the help.

Topic by d-stan1987 2 years ago  |  last reply 2 years ago


Regen Braking Motor Controller

Good morning.... Quick question regarding motor controllers with the facility of regen braking..... For a project of mine I am creating an EV (with a dune buggy chassis), which needs a system to recharge the batteries when been driven or 'towed' by an external force. I've been looking at a 4QD motor controller, which has the regen braking system already built in. My idea is to use the back EMF to charge the batteries. This in theory is quite similar to regen braking, having done a bit of research, and also with some info from the 4QD site itself. I know that if the back EMF is to great, I risk damaging the motor controller. But if there was a way to regulate the back EMF (either by controlling the speed it is been externally driven or with use of electronic circuitry), could I essentially recharge the batteries using this motor controller???! Thanks in advance, Dave

Topic by D__Humphreys 6 years ago  |  last reply 6 years ago


Circuit for electric vehicle? Regenerative braking / free-wheeling?

I'm working on a circuit for an electric trike I plan to build for the local EV challenge competition. I plan to incorporate regenerative "free-wheeling" to recharge the batteries on the down hill sections. S1 closed and S2 open to accelerate the vehicle. S1 open and S2 closed to recharge the batteries while freewheeling down hill. Batteries: sealed lead acid batteries 12V or 24V (depending on motor) Motor: brushed DC motor Would this kind of circuit work? Is it possible to recharge SLA batteries in such a way? Any help and/or suggestions is appreciated. PS. I know it would also be possible to implement regen braking using a full H-bridge, but i think we would be doing more freewheeling than braking on the race track.

Question by mulan2015 5 years ago  |  last reply 5 months ago


Charging BoostCaps

I recently got a few of the 3000 farad 2.7 boost caps from electronic goldmine.  I have a quick question about charging them.  Applying a higher than rated voltage before the capacitor is charged all the way would be fine, right?  The voltage drop should cause the source voltage to approach 0, thusly below the 2.7 volt rating.  As an extreme example, lets say you simply hooked up a 9 volt battery to it.  Since the battery can only supply like 200mA, the voltage drops to nearly 0 as the capacitor appears to be a dead short.  The dielectric (or ion exchange or napheon membrane or whatever it is in a ultracap, lol) should be fine, correct? My main goal is to later hook up one or two of these for a regenerative brake system of something like a small gokart or bike or something.  Stopping at 30mph is like (assuming 200kg total mass) 20k joules, and each one can hold about 10k joules, and assuming a max efficiency of like 30 or 40% (I think itd be much lower, though), these capacitors could brake a gokart going fairly several times without having to be discharged inbetween cycled (but of course they would be).  For braking, could these essentially be hooked up directly (of course with pwm, and other things, but in essence:) to the motor with a little protection circuitry to prevent overcharging the capacitors?  Or would the higher voltage instantly puncture and destroy the boostcap?

Topic by guyfrom7up 8 years ago  |  last reply 7 years ago


Help with electric bikes?

I am designing an electric bike (gas prices at $4 means I need one) and had a set of prerequisites to fill, and was wondering if anyone here could give me a quick hand. First thing is, I'd really like for it to have regenerative braking of some kind to extend the range, but am very unsure as to how to do this. I also plan on charging the bike at my school; so a built-in charging unit will be a necessity. I need a range of about 10-12 miles on a single charge, is this too much to ask? The plan is to use a pair of 12v 8 amp-hour Lead-Acid batteries (http://www.sciplus.com/recommend.cfm/recommendid/14608) and a 12vDC cordless drill motor to provide power. Is this too "weak" of a system? I have a 10-speed mountain bike that I'll be using as the base frame. Any help would be much appreciated.

Question by Kasaron 8 years ago  |  last reply 8 years ago


Human Electric Hybrid Vehicle

The HE Human Electric Hybrid Vehicle It looks like an interesting concept car. Although, it might be hard to find somebody who wants to pedal it. I really like the solar panels on top, and how on the downhill, it charges a capacitor for energy.This HE Human Electric Hybrid Vehicle concept uses the power of your muscles as well electricity stored in the batteries. It allows smooth and constant velocity both uphill (with the help of the electric motor), as well as downhill (when the wheel acts as a generator and charges the batteries). The vehicle can turn 360 degrees maintaining stability all the time. Additional power is acquired from photovoltaic placed on top of the vehicle as well as during de-acceleration from regenerative braking. Elderly and handicapped people that are unable to provide enough kinetic energy can also charge the batteries directly from the grid.

Topic by Brennn10 11 years ago  |  last reply 11 years ago


Hybrid cars - uphill strategies

I own a hybrid car (Honda Insight 2nd generation - CVT) and I'm happy with the fuel economy (4.3 L/100 Km  --  54,7 MPG),  but I think there is still room for improvement. My house is on top of a hill and when I get home I have to climb steep slopes. The batteries go low and the forced regeneration kicks in. (The car uses the gas engine to recharge the batteries.) When I get home the batteries are almost fully charged. The next trip is, of course, downhill and the high state of charge prevents me from getting the maximum advantage of regenerative braking. (Put in other words: I'm burning gasoline uphill to recharge the batteries that I could charge for free driving downhill...) How could I avoid/reduce forced regeneration? What strategies do you use driving uphill? Thanks

Topic by Fabio M 5 years ago


Electric bike from spare motors

Hi Everyone, my first post here.  I've been thinking of making an electric bike. Now there are bikes on the market that are $450+ and I have a spare one that I haven't touched in over 6 years lying around. With the recent improvements in DC electric motors, I think it's about time I gave it a shot at assembling an electric bike. The motor will likely come from an electric lawn mower, the battery will be a lithium ion battery rated for that motor (I can attach these into series or parallel depending on what motor I use). I've been looking at electric motors from Kogan.com.au (I'm australian)  Either one of these http://www.kogan.com/au/buy/18v-lithium-ion-cordless-garden-tool-set-3-piece-set/ or http://www.kogan.com/au/buy/recharge-mower-electric-lawn-mower The cheaper one more likely. If I should source a motor another way then I'm all ears.  My questions are: Would the motors in the first link be powerful enough (they use the same battery as an electric drill) How would I attach the motor to the bike so that I can ride and engage the engine when I want? How would I mount it so that I can use regenerative braking? I was thinking of using a clutch sort of mechanism attached to the wheel axle, again I'm all ears. And if anyone's done this already, what type of hazards am I going to face? (that probably aren't obvious, safety first!) I also thought of using a petrol engine from a lawn mower but an electric bike seems more appealing to me. :) Thanks all

Topic by majuules 4 years ago