MoTeC Global Forum

I have a pdm16, adl2, and m880 ecu. How do I control an electric water pump so that it controls the temperature of the engine by varing the speed of the pump?

Hi,
Both the M880 and the ADL2 have the capacity to generate a PWM signal to control an electric water pump. The M800/880 has a dedicated electric water pump controller function (aux output function 132, thermo pump). A similar function could be achieved in an ADL2 using an AUX output, a combination of 3d tables and user conditions. Depending on the maximum current drawn by the pump you may need an external driver to switch high current to the pump. This can be done using a high speed solid state relay or shortly we will have a new product for sale (DHB) that will be capable of driving very high current to one or two electric motors.

Has anybody thought or tried using Igniters(Ignition Modules) wired in parallel to drive a load?

Ignition modules are nothing else than a transistor with high voltage protection. Check datasheet for max current and max power they can handle.
Connecting modules in parallel will work, but be carefull. Current will not split in two equal half, due to differences between modules. Better use a module with multiple drivers, connected in parallel.

Angelo

Tripple channel igniter works well for PWM fuel pump control. Fitted CPU heatsink on back of igniter to get rid of heat. It heats up quite a bit, but with the heatsink it is good.

Im still wondering at what freq most guys control their PWM fuel pumps

High frequency give better accuracy in speed/pwm ratio. Current will remain close to constant in the motor. At low frequency, current fluctuation is higher and speed control is bad at low PWM. For example, at work, we use 16kHz for 0-6 amps motor.
Connect a free wheeling diode in parallel with motor. It should be connected on the module or transistor side, not on the motor. This will lower EMI radiation, but its main function is to allow correct PWM drive.

Angelo

By Freewheeling diode you mean flyback diode right? ( to suppress flyback voltage)


Secondly, you say that it should be on the transistor side and not the motor side. Do you mean on the same wire, just as close as possible to the transistor side and not close to the motor? Wonder why this would make a difference....?


Thanks

The leads act as aerials and transmit the frequency induced in them by the power. putting a twist in the leads like the can bus will attenuate the RF but shielding is better like on good rca, audio and hdmi cables etc. hope that helps