1. Control relays come in electromechanical and solid state varieties and can have single or multiple poles, throws, and breaks. Electromechanical relays use contacts while solid state relays use transistors. 2. Timing relays are used to control timing functions and can be on delay, off delay, or on/off timing relays. They are activated by a coil and timing circuitry. 3. Magnetic contactors are used to control electric motors and other high power loads. They contain fixed cores with moving contacts that make and break main and auxiliary circuits based on the state of the coil. Contactors allow direct starting and control of motors.

1. Control Relay
Control relays
Electromecanical Relay
Solid State Relay
electrical relay
electromechanical relay

2. electromechanical relay
NC NO
11
NO

3. relay
Pole: pole
single pole
double pole
single pole double pole
pole
pole

4. Throw: throw
pole
13 single throw double throw
double throw
NO NC
Break: break

5. NO NC
pole, throw brake

6. electromechanical switching
solid-state
e
lectromechanical relay
Timing Relay
On
DelayTiming Off Delay Timing

7. ON Delay TimingRelay
S1
coil 1 (TR1)
TR1 5
ON Delay Timing Relay

8. S1 coil
TR1 5
TR1
PL1
5 S1
coil TR1
TR1
PL1
S1
Off Relay Timing Relay
Off Relay
S1
TR1 Off Delay

9. TR1 PL1
S1
TR1
5
PL1
Off Delay
Magnetic Contagtor

10. Contactors)
2
2
1. Main Contacts)
3 3
3
Normally open;N.O.
contact) 1, 3, 5

11. L1, L2, L3
2,4,6 T1,T2,T3
2. (Auxiliary Contacts)
holding" maintaining contact"
13, 14
1
N.O. 2 23, 24
31, 32
41, 42

12. 1.
2.
3.
1.
1.) (Fixed Core)
(Shaddedring)
2.) (Stationary Core)

13. (Moving Contact)
2. (Coil)
A1- A2 a-b
3.
Contact)
--
- Main Contac)
- (Auxiliary Contac)
2
NormallyOpen:N.O.)
NormallyClose:N.C.)

14. ON)
3
3 7.5

15. (Direc Start)
5 - 7
1.
2.
3.
4.
5.

16. 5
3
1.
2.
3.
75%
2
1.
2.

17. Interlock 2
Pushbutton
2
1. K2 K1
2. K1 K2

18. 1.
S2 K2 K4T
-------
K2 4 K3 2
K1
2. K1 S2

19. N.O.) K1
3 K2
K4T Star)
3.
K4T K2
N.C.) K4T 1
N.C.) K2
4
K3
N.C.)
K3 1 K2 K4T
K1 K3
Delta)
4. S1(St
op)

20. 1. K1 K2
2.
K1 K3
3. K1 K2