Introducing MegaResistors

Introducing MegaResistors

Posted by Theresa Hoffman on Jun 19th 2024

There are times when having a manufacturer have a number of different product categories is nice.

There are also times when having a manufacturer focus on a category and absolutely crush it are also nice! For most variable frequency drive manufacturers, offering brake resistors is done as a courtesy but certainly not their focus.

Lead times can be long and support hard to come by.This is where MegaResistors comes in! When we say they do power resistors, we mean they can and will be able to solve your power resistor issue!

Who is MegaResistors?

Founded in Canada in 2008, MegaResistors specializes in manufacturing high-quality power resistors designed for demanding and critical industrial applications.

Proudly manufactured and designed in Mississauga, Ontario, all their products adhere to ISO 9001:2015 standards.

Additionally, MegaResistors products meet a wide range of national and international standards and codes (UL, NEC, CSA, IEEE, NEMA, and IEC). They also offer custom solutions to cater to specific application requirements.

What is a Dynamic Braking Resistor?

In simple terms, a dynamic braking resistor is a device that absorbs electrical energy and converts it into heat.

It's commonly used alongside Variable Frequency Drives (VFDs) that control electric motor speeds. When a VFD slows down or stops the motor, the motor can act like a generator, feeding electrical energy back into the VFD.

This can cause the DC bus voltage (internal voltage level) to rise too high.

Here's where the dynamic braking resistor comes in. By adding it to the system, the VFD can divert this excess electrical energy to the resistor.

The resistor then safely dissipates this energy as heat, preventing the DC bus voltage from exceeding safe limits and protecting the VFD from damage.

Pros of using a Dynamic Braking Resistor

  • Safe Voltage Levels- prevents the DC bus voltage from getting to high, protecting the VFD from damage caused by overvoltage
  • Longer Equipment Life- by maintaining safe voltage levels, dynamic braking resistors help extend the lifespan of the VFD
  • Faster Braking of AC and DC motors- enables faster deceleration by dissipating the motors energy as heat

Cons of using a Dynamic Braking Resistor

  • Energy Loss – where energy efficiency is a priority, the energy dissipated by the resistor represents energy loss
  • Environment – due to heat generation, these resistors aren’t ideal for electrical panels or near sensitive equipment
  • Sizing Challenges – an undersized resistor could overheat and fail, while oversizing may be unnecessarily expensive

Marshall Wolf Automation is an authorized MegaResistors distributor, for more information on their products contact us!