PHASE FAILURE RELAY CONNECTION IN MOTOR STARTER
Peace be upon you, in today's lesson we will learn about an important element that is used to protect electrical devices such as motors and others, and it is dependais de phase or what is called a phase absence tracker, I know that it is a long name for abbreviated as rolly de phase sequence, and it is known when someone is interrupted Vases lead to many problems, including combustion of the motor or the load connected to it, especially in a three-phase system because in a single-phase system there is no effect, and among these problems we mention:
Stopping or weak movement of the engine is harmful to its long-term combustion.
There is a buzzing sound in the engine coils and smoke emission from them when the engine enters the combustion mode.
Reversing the direction of rotation of the motor leads to damage to the mechanical load that the motor runs (it is considered rare).
High ampere draw (current) to compensate for the broken phase torque.
The occurrence of budge, vibration and noise from the engine.
For this, we must connect the relyais de phase device, especially in the pumps that are located underground, because there is no indication of the state of the motor, unlike the motors located in places where it can be observed.
How to connect the phase FAILURE RELAY :
The three phases are connected in places L1, L2, L3, respectively, while respecting the order of the phases. There is a device that arranges the phases, and you can search for it in the market. And then one of the phases or the neutral is connected to the open points NO, after which we close our control circuit (you can choose any place that suits you to install the device, provided that it is in series with the control circuit).
An indication lamp can be connected to the other points to know the status of the device, and when the lamp lights up, this means that there is a problem of interruption of one of the phases.
How the dependais de phase device works:
When one of the phases is cut off, the device changes the position of the connections from closed to open, and the one connected to the indication lamp from open to closed, which leads to the ignition of the lamp, which indicates that one of the phases has been cut, and it stops the motor by cutting the control circuit, because the points are connected in series with the control circuit.
note :
There are devices that combine phase sequence and under and over voltage protection (protection from high voltage). These devices provide excellent protection and it is preferable to install them for large and expensive engines.
There are devices that come with several connections of the type NO and NC, so you have to choose the appropriate one for you. This device, to which we applied the explanation, comes with a closed point and an open point.
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