There are specs listed in product descriptions (if you happen to’re fortunate) after which there may be actuality. The gulf between the 2 is usually huge, particularly when buying by on-line marketplaces with unscrupulous sellers. Bubs needed to know if his DC motors really meet the desired torque figures, so he constructed his personal dynamometer for the job.
A dynamometer is an instrument that measure the torque of a turny factor. You’ll continuously hear automotive guys discuss utilizing a “dyno” to search out goal energy figures for his or her engines, to allow them to impress associates on the drag strip. However these measurements are helpful for every kind of functions, together with electrical motors for robots and machines.
Bubs constructed an inertial mass dynamometer, which measures torque by taking a look at how rapidly an electrical motor can speed up a rotating mass. That methodology is good for a DIY dyno, as a result of it actually solely requires a inflexible body, a mass to spin, and a few sensor to watch rotational velocity over time (and subsequently acceleration).
The body and virtually every little thing else on this dyno had been 3D-printed. An opto-interrupter detects tooth in a 3D-printed wheel to measure velocity and acceleration, with a rotational decision of two levels. The spinning lots (they’re known as “load plates,” apparently) are 3D-printed discs with embedded metal bearing balls. Bubs designed these to be stackable, so he can modify the mass to swimsuit the torque of the motor being examined.
All Bubs must examine a motor is an influence, a logic analyzer to watch that opto-interrupter, and no matter management enter the motor wants.
In concept, this could work nice. However it instantly broke throughout testing. 3D-printed components aren’t at all times sturdy sufficient for the job. Nonetheless, as a result of the thought is sound, Bubs can rebuild his dyno stronger than earlier than and begin testing motors.
