Brake resistors allow energy regenerated from the motor to be dissipated, allowing shorter stopping times to be achieved with high inertia loads. Invertek brake resistors are suitable for light duty loads, and can be mounted directly to the drive heatsink for a convenient, space saving installation method.
EMC filters reduce the transfer of electromagnetic noise between the drive and mains power supply. All Optidrives are fitted as standard with an internal EMC filter, except where specified by the customer, and for most industrial applications, this will be sufficient. In the event that a higher level of filtering is desired or required, the external EMC filter can be added to either a drive which already has the internal EMC filter, or a drive without EMC filter. Best performance is achieved by using a filtered drive and the appropriate external EMC filter.
Input chokes can be used to reduce the supply line harmonic currents and voltage distortion generated by almost all inverter drives on the market today. Invertek Drives have selected a range of chokes matched to the Optidrive range to provide the best reduction in supply current harmonics whilst also providing enhanced protection for the Optidrive against transient voltages ('spikes') or other mains borne interference.
Input chokes are available for the complete range of Optidrive products, and are recommended for use in all installations and in particular:
- where the local mains supply quality may be poor or unknown
- where high current switching loads such as large DC drives or soft starts are operating
- where the mains supply impedance is low
- in remote areas prone to lightening strikes
Output filters should be used whenever long motor cables are fitted between the optidrive and the motor. The additional inductance helps balance the effect of the cable capacitance, and protect the motor against possible damage. Output filters should also be used whenever a non-inverter rated motor is used.