Simple Testing Machine

what's it for?
The reason for making this simple machine is this: in the past if I had motor kits sent out directly from some suppliers in China to a customer, there would occasionally be some problem as some of the parts had not been tested or there had been some changes in design of controller or motor. Since now I have a small office/storage space and someone working there (Shen) in China, its possible for all the kits to be wired up and checked that everything is working ok. The idea of the machine is not to measure wattage output or to get torque graphs, its simply to make the motor run at maximum power for a very brief period to make sure all is ok and working correctly. The only meter on the machine is an ammeter so Shen can make sure he gets the motor under load to near the maximum amps that the controller can supply. It can be quite hard to get the controller to max. amps as it requires alot of force pushing down on the machine. When I tried myself (my weight is about 80kg) it was not possible to stop the motors from spinning completely (max. amps) unless I bounced my whole weight down on the machine, the motors are surprisingly powerful.
So using this simple device its possible to check
1. controller is working correctly
2.wiring connections are all connected correctly
3.brake handle cut off switches are working 
4. throttle is working, and led lights on throttle are working
5. motor is functioning correctly

All the parts or kits that I send out are tested before sending (not only so customers know they will get things that are working, but also so I dont have to send out new parts which costs me a fortune!) This includes everything in the kits: controller, motor, throttle and brake handles.
Other parts such as battery chargers are also tested before sending to make sure all is ok.

How the motor kits are tested:

One of the main things I've been concerned about in the past when getting kits/parts sent from china was the lack of testing that was done before the kits/parts were sent to customers. It just wasn't possible for me to make sure all parts were tested and this did lead to some rather frustrating circumstances. So the only solution I could come up with was to set up a small office/workshop/storage place in China where the kits/parts could be tested by someone I've trained myself. Because I'm doing this on a low budget, you could say a shoe-string budget, I've had to come up with some way to test the motors/controllers while they are under load. Its not practical or economically possible at the moment for me to spoke all the motors into rims put in a bike then test ride. So below is the solution I came up with, simple but very effective.

I've made a very simple machine that uses a leather belt on the motor to create drag and put the motor under load. This idea of using a leather belt came from noticing that the drum brakes that are used on ebikes in china use leather as the brake linings. Below are some pictures of how it works:

The test machine is just made from square steel tube welded together.


Pushing down hard with my whole body weight by placing my foot on the frame (large red arrow above) using a fulcrum effect
to magnify the force. A leather belt placed around the motor takes all of this force and creates are resistance against the motor
turning.


An ammeter is used to measure the current being drawn from the batteries when the motor is under load. By placing my whole
body weight on the frame it gives enough force against the leather belt to slow the motor and be able to measure the maximum
amps the controller is using. This can also be used to measure and adjust the maximum amps which is variable by a small screw
on the controller. It is possible to stop the motor briefly if I put as much of my body weight as possible on the frame.



Shen connecting up a controller/motor/throttle and brake handles
for testing.
Video of test machine:http://video.google.com/videoplay?docid=7160445582054465758
(note in the video the needle on ammeter is sitting on about 15amps, excuse the quality of the video it was taken on a mobile phone)

beware of spray ebike company: more info

back to home page
Copyright 1998-2006 by Brett White on all images/text/information and graphical materials on this website.