We indeed use helical-wormgear motors (for a picture see the attachment). The advantages are:
- less costly motors
- the motor keeps its position on standstill
- a smaller less costly brake is needed because the inertia is smaller since the motor comes very quickly to a standstill (because of the wormgear)
But as said there are disadvantages:
- for the same torque you need a bigger motor
- the lifespan of the motor is shorter which is a disadvantage with simulators for commercial use (in our case this is not a problem)
- the motors must be mounted in angle but as you can see in the pictures that doesn't pose a problem in our design.
For the encoders there is another solution. You can buy a motor with hall-sensors built in (a very cheap option). These hall sensors give the position of the motor up to 60° degrees accurate. But since the sensors are mounted on the electromotor and not after the gearbox the accuracy can be divided with the gear ratio. For instance, my motors have a gearratio of almost 100. This means that with those hall-sensors I can have an accuracy of 60°/100 = 0,6°. It would be cheaper than buying a separate encoder and you don't have the hassle of connecting the encoder.
Should I have to buy the motors again I would choose the same motors but with hall-encoders, a BMK-brakerectifier (for fast brakeswitching - new installed) and forced cooling. Now we also have to install extra cooling because of the extra heat generated buy the raped movement of the motors. And for other readers, watch out with the how the axis is placed (left or right). I bought two identical motors but because the shafts came out on the same side I couldn't mount them. I had to take off one terminal box to be able to place them. And refitting a motor costs the same as a new motor