DIFFERENCE BETWEEN SOLID STATE RELAY & ELECTRO-MECHANICAL RELAY

WHAT IS SOLID STATE RELAY

By using a solid state relay we can control load currents, by using solid state switches such as SCR’s or a power transistor. solid state relay can switch without the contact, a solid state relay is mainly an electrical switch which consists of the electronic component. It doesn’t have any moving parts it is because there are no mechanical contacts for opening and closing, solid state relay uses semiconductors for its operations.

OPERATION

The input signal enters the device through isolation mechanism and this input signal will control switching and by this isolation the high power load current can be removed in case of failure, while switching of the load current through the inductive load, a sudden interruption to current flow will create a rise in voltage, and this voltage is harmful to the relay, by the snubber a reverse connected diode will create an alternating path around the relay switching device and thus the inductive element can discharge.

Electromechanical relay

An electromechanical relay does the switching by using an electromagnetic device it opens and closes the electrical contacts to turn a load off and on, the moving component which is present in an electromechanical relay is an armature which is attracted by the magnetic field

OPERATION

It is usually an electrically operated switch and it will interrupt a circuit by moving electrical contacts, this relay has a movable armature, movable contact, and stationary contact the coil is energized by the supply and then the relay contacts movable and fixed is attracted, the relay which is energized by electrical supply and it does mechanical function then it is a electromechanical relay.

SSR APPLICATIONS

  • It can do continuous switching due to the lack of contacts and there won’t be any damage
  • High speed
  • It can be used in a dusty environment
  • It can be used in a hazardous area where the gas presence is seen

EMR APPLICATIONS

  • It can be used were wide output range is needed
  • Initial budget is very low

ADVANTAGES AND DISADVANTAGES OF SSR

  • It has a very long life, there is no contact for wear and tear
  • It is resistant to shock and vibration
  • It has fast switching capability
  • Different switching modes
  • only one contact available per relay
  • when the switch is open offstage leakage current
  • overheating

ADVANTAGES AND DISADVANTAGES OF ESR

  • low initial cost
  • no heat sink is required due to low voltage drop
  • it can switch AC or DC
  • low life due to the wear and tear of the contacts
  • resistant to a voltage transient
  • no overheating
  • electric shock risk is less
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I was not aware of solid state relays. Thank you @ashlin. This is very helpful

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