ABB Starter Overload Relays
ABB overload relays are designed to save motors from thermal overloads, phase failures, and excessive currents. Thermal overload relays are economic electromechanical protection devices for the main circuit. When used in conjunction with contactors and motor starters, they afford reliable motor protection. Abnormal operating conditions are detected and acted on by the thermal overload function, which measures heat generated within the motor and disconnects the motor if the temperature exceeds safe levels.
ABB overload relays can be reset automatically or manually, offering versatility and adaptability to numerous applications. They are simple to install in control panels, requiring little space and no special tools, making integration straightforward. With adjustable trip class settings, ABB's overload relays can be optimized to work with motors of almost any size and with a wide array of operational profiles. They are available in several models that are compatible with virtually any type of industrial motor. In all respects, their performance is both precise and efficient. In terms of the simple overall task they perform, that performance is reliable and as close to foolproof as anything can be that works with electric motors.
FAQs
After a phase failure, does an ABB thermal overload relay require a manual reset?
Yes, after a phase failure, an ABB thermal overload relay typically requires a manual reset to restore normal motor operation.
Do ABB overload relays come with single mounting kits for installation?
Yes, ABB overload relays come with single mounting kits for easy installation.
Motor Control Basics
Motor control allows operational control of electrical motors in various environments.
Motor control circuits provide a safe way to operate electrical motors. Back when motor control circuits were in their infancy, it would have been common to see a simple disconnect switch that would be used to turn on and off a motor. Depending on the size of the motor and how much voltage was required, operating this disconnect would have been dangerous, with a very high possibility of arcing or electrocution. Not to mention that when the disconnect was actuated, the large amount of inrush current would have damaged the motor over time.
In today's motor control circuits, there are a few common pieces of hardware.
A circuit breaker is used to protect the motor and any hardware downstream. A contactor and an overload relay are connected together and function in tandem to allow for remote and safe operation of the motor. The contactor functions much like a relay, allowing for a smaller electrical circuit to remotely close the motor contacts, starting the motor. The overload relay is designed to protect the motor in the case of a prolonged overcurrent event. These two devices are wired in series, so that if the overload relay detects an overcurrent event, the contactor will open the motor contacts, shutting off power to the motor.
The other two most common types of motor control hardware are a soft starter and a Variable Frequency Drive (VFD).
Both of these devices function in a similar way to the motor circuit with some added functions. The soft starter is designed to reduce large inrush current to the motor upon startup. This “soft starting” of the motor will prolong its life and allow for safer operation. The VFD performs the soft start functions, but also allows for speed control of the motor. This speed control is critical in many different environments and has made VFDs one of the most common and safe to use motor control circuits today.