Explosion Proof Motors
Explosion proof motors are intended to be safe to use in environments where one might expect a potentially hazardous (explosive) mixture of gases, vapors, or dust. Such electric motors do not contribute to an atmospheric ignition because they are constructed to contain any internal explosions. They achieve this remarkable feat of safety through a careful mixture of design and closely followed safety standards and certifications. Most explosion proof motors are ATEX certified, meaning they meet the safety requirements outlined by the ATEX directive for use in explosive atmospheres.
An Explosion-proof motor is usually built with robust materials like cast iron or steel. These materials can endure the sheer force of the blast without bursting apart themselves, thus ensuring that the motor is capable of containing the explosion within. The design of an explosion-proof electric motor takes into account the temperature of the gases that escape after the explosion and before they enter the normal environment of the motor’s operation.
Products
FAQs
What type of explosion protection is needed for motors in explosive dust atmospheres?
Motors in potentially explosive atmospheres require dust ignition-proof (DIP) protection, which ensures that the motor is tightly enclosed to prevent dust ingress and contains any internal ignition sources, preventing ignition of the surrounding dust-laden atmosphere.
Motor Starters, Soft Starters and VFDs
Motor Starters
Motor starters safely start and stop a motor in industrial applications. They are designed with a contactor, overload and circuit protection. They are used when basic motor control is required, where torque on the motor is not a concern and speed control is not needed. The advantages of motor starters include: lower cost, allows for remote operation, allows for monitoring of motor state (with the use of auxiliary contacts) and they are safe and efficient. The disadvantages include: high inrush current that can cause fuses to blow and breakers to trip if the inrush is too high, and the starter will allow a full torque to start the motor which can cause the motor to ramp up to full speed very quickly potentially causing the motor to wear and degrade prematurely.
Soft Starters
Soft starters protect motors from inrush current by gently ramping up the motor to full speed. They provide all of the same functions as a traditional motor starter. The advantages of soft starters include: they are less expensive than a VFD when only startup control is needed, they are a smaller system than a VFD where space is a concern and they prevent unwanted torque upon startup, prolonging the life of the motor. The disadvantages include: they are more expensive than a traditional motor starter and they do not allow for full speed control.
VFDs
A Variable Frequency Drive (VFD) allows for the slow ramp up of a motor during startup and the slowing down of the motor during shutdown. It also allows for full speed control during the entire run cycle of the motor. VFDs provide the same functions as both the traditional motor starters and soft starters. The advantages of VFDs include: full speed control (start, stop and in-between), more custom control and monitoring, energy savings due to efficient motor usage and less wear and tear on the motors. The disadvantages include: they are more expensive and larger than other motor control options and they generate heat that may require fans or AC units.