I have a student who is running two V4 Motors on a puncher.
Today he replaced the two V4 Motors with one V5 motor. We expected the performance to increase because we have heard that one V5 is 2.5 V4s. We were disappointed to find that it couldn’t cycle the puncher at all.
What’s the best way to test a motor to see if there’s a problem with the power?
Their is no way to test the power like a 9 volt for the old motors. Its probably a programming issue or a wiring issue.
Two 393s will beat a V5 motor at stall torque at 100RPM (V5 motor has stall torque of 2.1Nm wheras the 393s have 1.67Nm each). Where the V5 motors really shine is at sustained loads. They do not overheat nearly as quickly as 393s and thus in sustained load applications (such as flywheels or drives or lifts) will likely perform like 2.5 393s (No public testing has been conducted AFAIK). I’d encourage your student to look into flywheels, especially if they are using V5 as a the motor distribution looks much more efficient for a V5 robot.
Edit: Also make sure the student is using a 100RPm cartridge for the V5 motor; the default is 200RPM.
The default gearing for V5 motors is 200 rpm so it’s more like the torque of 2.5/2 393 motors.
V5 motors are current limited to below their maximum capacity, and the green gearboxes cut their torque in half from what it could be. Two 393 motors with 100rpm gearboxes will have more stall torque than a single V5 motor with a 200rpm (green) gearbox. If he changes the gearing on the puncher to work with the lower stall torque he will get better results from the V5 motor than the two 393’s.
As for ways to test V5 motors, they have telemetry built-in that is accessible through the programming API. This project gives a bit of an idea of how to poll that information in Robot Mesh Studio, and can be run to check how that single motor is doing.
As a bit of a background, electric motors have maximum torque at 0 rpm, but generate a lot of heat to do so because this is also the speed at which they draw the most current. Consequently, it is much friendlier to motor and battery life to run electric motors at as high of a speed as practicable. V5 motors can draw enough power that their unlimited 0 RPM draw would generate heat far faster than it can be dissipated, so they are prevented by their firmware from drawing full power under a certain RPM. Once past that speed, though, their full potential can be used and will greatly outperform a 393.