Manual Starters
A manual motor starter is a simple and reliable device that allows an individual to start and stop an electric motor by hand. They are often used for starting smaller motors, where no automation or remote control is required. Inside, there's a switch mechanism that the operator uses to engage or disengage the motor.
An essential benefit of manual motor starters is that they offer protection against overloads. This is typically achieved by incorporating an overload relay—an either thermal or magnetic—directly into the starter. The relay detects excessive current and, in case it finds some, disconnects the motor to keep it from overheating and/or exploding. Overload protection is critical for not just the operation but also the service life of a motor.
Compact and simple to set up, manual motor starters are often installed directly on the motor or nearby for quick access. Being tough and rugged, they can withstand the sorts of conditions you'd normally find in an industrial or commercial space—so you don't have to worry about them failing under stress.
Products
FAQs
Do manual motor protectors provide thermal overload protection and short circuit protection?
Yes, manual motor protectors provide both thermal overload protection and short circuit protection to ensure the safe operation of motors.
Does a motor controller have shunt trips and auxiliary contacts?
Yes, a motor controller often includes components such as shunt trips and auxiliary contacts to enhance its functionality and safety features.
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.