Q&A Forum
I am trying to convert a John Bean LAD2000 emission dyno to YourDyno. The info tag for this dyno says its base inertia weight 2000lbs inertia. Roller diameters are 8.5in. The roller has 64 pulses per rpm and I'm using the original power supply for each brake. I traced it out the brake control and it was 5v PWM but I had to click the inverted check box on the software. I'm also using the original load cells and calibrated both already.
I have one problem, the rollers are not directly connected to the brake. It has a cogged belt that looks like the car timing belt. That belt is connecting the 2 rollers together with 80 teeth on the rollers and 34 teeth on the flywheel. My 2 question to the forum is, has anyone dealt with this? Will I be able to make this work?
On the RPM side there is an important rule: The RPM sensor needs to read the RPM of the brake. If the RPM sensor is on the brake already, then we don't need to care about the gearing done by the cogged wheel.
If the RPM sensor is on the rollers and the brake is geared up, then you need to calculate the effective number of teeth the dyno sees per brake revolution and use this in the Pulses per revolution. It that case it would be 64 * 34 /80 teeth per (brake) revolution.
I find it hard to believe you need to invert the PWM signal for the brake control. I would try with an analog signal, 0-5V. This is the most common power supply control scheme. You need to swap the jumper inside the box to get analog.
On the RPM side there is an important rule: The RPM sensor needs to read the RPM of the brake. If the RPM sensor is on the brake already, then we don't need to care about the gearing done by the cogged wheel.
If the RPM sensor is on the rollers and the brake is geared up, then you need to calculate the effective number of teeth the dyno sees per brake revolution and use this in the Pulses per revolution. It that case it would be 64 * 34 /80 teeth per (brake) revolution.
I find it hard to believe you need to invert the PWM signal for the brake control. I would try with an analog signal, 0-5V. This is the most common power supply control scheme. You need to swap the jumper inside the box to get analog.
I'll correct the rpm sensor today. It does have another rpm sensor on the flywheel shaft. It's a bit different, I would have to see if it's compatible or how to connect it. It has 4 wires instead of the 3 that it's using on the drum side.
The mosfet driver it's using for the brake is a MIC4429. It says the 4429 is inverted and 4420 is non inverted. I don't know if its pwm or not though. Would someone here know about this chip? Later when I get home I'll try the jumper you are talking about to see what happens.
Appreciate the help.