Maximizing Gearmotor Speed Range

^{by SEW-EURODRIVE}
If you run your variable frequency drives at 60Hz and below, you are not alone. Nearly all the VFDs in North America operate below this nominal frequency threshold. Yet a growing number of high-performance gearmotor systems will benefit from a more aggressive control approach that cranks VFD operating frequencies up to 80, 90 or even 120Hz.

Under the right circumstances, operating a VFD at these higher-than-usual frequencies can enhance gearmotor performance significantly in the following ways:

• Increasing stability by reducing inertia mismatch
• Widening the available speed range
• Eliminating motor overheating at low speeds
• Enabling the use of smaller motors

Reaping these benefits, however, requires some extra design attention. When you drive motors above 60Hz, gear ratio and available torque change. And these changes need to be reconciled with the load torques.

In this white paper, you’ll learn why it can be a good idea to push gearmotors beyond 60Hz. You will also learn how to break the 60Hz barrier safely and effectively. Finally, we’ll walk through a common example that will show you how to select the proper gearmotor for a wide speed range.