# Using two motors and belt drives to drive one shaft

I have an application where I need two motors to drive one shaft via the use of belt drives but I need help on how to arrange such a system. The system constraints are:

1. motor type - induction motors $(48\ \textrm{V}, 750\ \textrm{W})$
2. both motors will have pulleys of same dimensions
3. both motors will drive single o/p shaft with bigger pulley attached to it

Please see the image of my current work, and please let me know if with this arrangement I can have more output speed and torque. If you have any other ideas, please let me know.

• What are the dimensions of your motors & shaft and what is the maximum size that you need the system to fit into?
– Fred
Jan 15 '16 at 5:29
• How do you plan to get both motors at exactly the same speed, and have exactly identical pulleys for the belts? Or are you willing to accept slippage and wear? Jan 15 '16 at 12:48
• What is your problem? You have explained what you want to do, but you haven't explained what problem you are having. You want to attach pulleys to a shaft, so do it.
– hazzey
Jan 15 '16 at 13:32
• Possible duplicate of Effective ways to drive a single shaft with multiple motors? Jan 15 '16 at 13:46

I would suggest something closer to the following:

Also when controlling the system, make sure the speed control is on only one of the motor shafts and you drive both motors with the same output from the speed control loop. In other words don't try to control the speed of both motors with separate motor controllers.

• thank you for this . I think this will work for me. and again thank you for your reply.. Jan 22 '16 at 9:30

Two issues I see: The belt tensioner(s) should be placed on the "slack" portion of the belt, not between the motor and the load - similar to a bicycle chain derailleur. The tensioner rollers are relatively small and may be smaller than the minimum backbend diameter specification of the belt.

My 2 cents:

1. Two motors for one shaft is not recommended because one motor will have more load (no motor can be exactly the same, even if same type and size) including induction motors.
2. Induction motor speed depends on electrical power frequency (and number of motor poles). But you can install bigger motor pulley & smaller shaft pulley - but this will make your torque lower.
3. More torque is certainly, since you use 2 motors. You can get higher torque by using smaller motor pulley & bigger shaft pulley - but this will make your speed lower.
4. Be careful that belt drives damaged when installed on very small pulley. Dented belt or notched v-belt can be used for small pulleys.