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Vector Drive Webinar Q&A
Will there be an option in the future for an encoder to create a closed loop system? If so, what would be the turndown ratio at that point?
Replies to This Discussion
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Permalink Reply by Michael Dillon on
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Not in this configuration. For closed loop, only a component solution is available.
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Permalink Reply by Glenn A. McIntyre on -
The standard units are rated for 30:1 turn down. That is a very wide speed range. It would be unusual for a process to require a maximum speed that is 30 times as much as minimum speed. I suspect that an application requiring the very low speed is because you are trying to use the speed turn down in lieu of gear reduction. It would be much better to change a pump selection parameter or the gear ratio to get the motor RPM up higher.
At higher speeds, the motor runs cooler and has longer insulation life. The speed regulation is tighter as well. Additionally, the HP capability of the motor is proportional to the motor RPM up to base speed. That means a 4-pole (1750 RPM) motor running at 175 RPM is only capable of 10% of nameplate HP. The torque rating is the same, but HP is proportional to torque and RPM.
If your HP requirement is 1 HP at a maximum motor speed of 600 RPM, you would have to use a 3 HP motor with no gear reducer. However, using a 3:1 gear reducer would multiply the torque by a factor of 3 and allow the use of a 1 HP motor.
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