Different types of Motor Starters

Motor starters are electro-mechanical devices that start or stop electric motors through the use of manual or automatic switches, and offer overload protection to motor circuits. Moreover, they are usually utilized in cases where electric motors are operated over a certain horsepower.

They can be designed with specifications that meet various intended application criteria, some of which include starter type, number of phases, current, voltage, power ratings, and other features. With this in mind, there are several types of starters, including manual, magnetic, soft-starts, reversing, and combination types. 


Manual motor starters are utilized in full voltage, across-the-line applications for small to medium sized single- and three-motors. Typically equipped with an ON/OFF switch and an overload relay, manual motor starters do not offer motor power disengagement in the event of power interruption. This is especially helpful for small pumps, fans, and other devices, allowing them to resume normal working conditions after power has been restored.

In some cases, manual motor starters will offer under-voltage protection as a way of de-energizing the starter circuit after a power interruption. Under voltage protection is ideal for machine tools and woodworking equipment, both of which require certain safety protocols.


Magnetic motor starters, on the other hand, rely on electromagnets to close and hold contactors rather than using mechanical latching of ON/OFF switches. They are typically used in across-the-line applications and as reduced voltage starters for single- and three-phase motors. Additionally, those that use momentary-contact pilot devices necessitate a restart after a power loss, otherwise, low voltage conditions can make the contactor drop off. Furthermore, magnetic motor starters can be wired to restart motors automatically if the application at hand requires it.


Soft starters are different from their counterparts in that they feature a digital control to electro-mechanical starters. As such, they enable motors to be brought up to speed, preventing damage to drive trains and products, all the while avoiding overtaxing the electrical distribution service which is caused by the high inrush current of medium and large motors undergoing full-voltage starts.


Reversing starters have two sets of contactors that provide reversed leads to motors, allowing them to turn in either direction. More than that, they offer electrical and mechanical interlocks to prevent both sets of contacts from closing simultaneously.  


The last type is a combination starter, which houses units that incorporate disconnects and short circuit protection alongside the motor starter components.


Motor starters serve as special purpose electrical devices that can handle high electrical current while protecting motors from overload during normal operation. They use thermal or magnetic overload relays to introduce a time delay during start up wherein the motor experiences a high inrush current. If the motor jams, often referred to as a locked-rotor scenario, it draws this same inrush current continuously. This forces the overload relays to overheat, ultimately dropping out the switch or contactor, and as a result, the motor.


If you find yourself in need of motor starters such as clamp motor starters, interlock motor starters, cover motor starters, coil motor starters, or other related parts, rely on Internet for Aviation. Internet for Aviation belongs to the ASAP Semiconductor Family of Websites, making us one of the only leading distributors that operates with AS9120B, ISO 9001:2015, and FAA AC 00-56B accreditation. More than that, with over 2 billion ready-to-purchase items at your disposal, you are bound to find what you need with ease. When you find an item that suits your operational needs, we invite you to fill out and submit an RFQ form as provided below. Within 15 minutes of submission, a dedicated representative will reach out with a customized solution that fulfills your part requirements.


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