pārpublicēts no:  http://www.electric-bikes.com/bikes/diag-03.html#throttle

Diagnosing throttle problems:

Symptom: Either the throttle sometimes works, or it doesn’t work at all AND the motor/controller smells OK.

Throttles come in three types: simple ON/OFF, potentiometer, and Hall Effect. With the simple two-wire ON/OFF throttle switches (used on Zappy, Tracker, Tomb Raider, Eboarder, etc.), start by unpluging the throttle from the the controller. Then, using a multimeter, measure the resistance through the throttle. It should be way high until you activate the throttle when the resistance will drop to near zero ohms. It it doesn’t drop, the throttle switch isn’t making connection. If you can’t repair it, replace it.

With the potentiometer type of throttle (used on Currie, GT, Schwinn, and Mongoose scooters with finned motors, Currie bicycles, PowerCats Tiger scooters, Lashout scooters and bicycles, etc.), start by unpluging the throttle from the the controller. Then, using a multimeter, measure the resistance (Ohms) between ‘common’ and ‘low => high’. The resistance should be below 100 ohms. As the throttle is activated, the resistance will rise to about 5,000 ohms. If initial resistance is 400 ohms, the motor/controller will think something is wrong and won’t respond. Also, measure the resistance (Ohms) between ‘common’ and ‘high => low’. The resistance should be about 5,000 ohms; as the throttle is activated, the resistance will fall to below 100 ohms.

Another test for the potentiometer type of throttle is to test the connection to the motor/controller. After unplugging the throttle wire from the motor/controller, turn on the power to the motor/controller. Then, use a paper clip to jumper between the two outer pins of the motor/controller’s throttle connection (red and brown in the drawing). Doing so makes the motor run and continue to run until the jumper is removed. WARNING: make sure the drive wheel is off the ground and the vehicle is secure.

With the Hall Effect type of throttle (used on Currie, GT, Schwinn, and Mongoose scooters with brushed motors, most Chinese-made electric scooters, bicycles, pocket bikes, mini choppers and go karts, etc.), start by probing the throttle wires while still connected to the controller. This may require that you insert sewing pins or needles through the insulation of the throttle wires. Then, using a multimeter, measure the voltage on the three pin leads from the controller. Normally, the red wire carries 5 volts from the motor/controller to the throttle for the Hall Effect power source. The white or green wire is the ground wire. The yellow wire returns the Hall Effect voltage to the motor/controller; it ranges from 1.0V (for OFF) to 4.2V (for top speed).

Here’s how the throttle voltage and Currie’s brushless motor/controller work together for many throttles:
There are 3 wires that go to the throttle, let’s call them SOURCE (black), SENSE (red), and GROUND (brown/common). With ground as reference: sense is at a constant +5V, SENSE controlls motor speed. Impedance from SENSE to GROUND is about 5Kohm, SENSE positive, power on. When SENSE rises above 110mV, the motor control circuit energizes. Below 180mV the motor doesn’t turn but it becomes resistant to turning backwards. Above 180mV the motor starts turning. No matter how slowly SENSE is raised the motor starts abruptly with a slight jerk. Motor speed rises in proportion to the voltage on SENSE until it reaches 3.6V at which point the motor abruply jumps from medium to full speed.’

These wire colors and behavior varies. For example, one Hall Effect throttle has a red wire (+5v), green wire (+4.2V) and yellow wire (ground) while a second throttle has red (+5V), green (+4.2V) and black wires (ground). ElectricScooterParts.com has further information including special bulletins.