SPST SPDT DPST DPDT SWITCHING
What is SPDTswitch!
What is SPDT relay?
DPDT,3PDT,3PST……..
What are they?
Heard about this ?..
SPDT …..single pole double throw
SPST…….. Single pole single throw!!!!!!
They are the one type of specification of switching devices like switches,relays , Contactors etc.
Relay contacts,switches , contactors etc important components used in many applications .Their primary function is switching . They either provides or break path for power supply through their contacts .In industries you can see a wide variety of switches,relays contactors etc .You will find lots of specifications also .They are classified in many different ways .one important way of classification is according to the poles and throws .This article explains about this .
Poles and Throws
The switching function of these devices are established through proper alignment of their contact mechanism in their normal and activated state .The path of electrical power is determined by the state of this contacts . Poles and throw specifies the functionality and provisions for electrical path one can make with this device in a circuit.
Poles
It is the terminal common to the connections . Single pole, double pole etc specifies the number of available poles or common connections.
Throws
Throws specifies the number of ways by which each pole can make connections .
Let us analyse some examples so that you will get clear idea about this poles and throws .Let us go through the classification of relays on the basis of poles and throws
SPST SPDT DPST DPDT SWITCHING
SPST
single pole single throw.
It has one pole and one throw .See the figure ..
1.It has one common connection to the circuit.So the number of poles is one .
2.The number of ways by which connections to the pole can make is one .So it is single throw .So such type of switch or relay is SPST .
SPDT
single pole double throw.
It has one pole and two throw .See the figure .
1.It has one common connection to the circuit.So the number of poles is one .
2.The number of ways by which connections to each pole can make is two .Each common terminal can make two connections .At normal condition it makes electric continuity with NC contact .And when activated it is switched to NO terminal .So it is double throw .So such type of switch or relay is SPDT .
DPST
DPST Means Double pole single throw.
It has two pole and one throw .See the figure .
1.It has two common connection to the circuit.So the number of poles is two.
2.The number of connections the each pole can make is one .So it is single throw .So such type of switch or relay is DPST .
DPDT
DPDT Means Double pole double throw.
It has two pole and two throw .See the figure.
1.It has two common connection to the circuit.So the number of poles is two .
2.The number of connections the each pole can make is two .So it is single throw .So such type of switch or relay is DPDT .
3PST
Means Triple pole single throw.
It has two pole and two throw .See the figure .
1.It has three common connection to the circuit.So the number of poles is three.
2.The number of connections the each pole can make is one .So it is single throw .So such type of switch or relay is 3PST .
3PDT
Means Triple pole double throw.
It has three pole and two throw .See the figure .
1.It has three common connection to the circuit.So the number of poles is three .
2.The number of connections each pole can make is two .So it is double throw .So such type of switch or relay is 3PDT
