Over Load Relay & Contactor for Starter
May 20, 2011 12 Comments
Over Load Relay & Contactor for Motor Starter:
Types of Over Load Relay:
- Class 10: Would Trip after 10 seconds.
- Class 20: Would Trip after 20 seconds.
- Class 30: Would Trip after 30 seconds.
- Over Load Relay should be set 115% to 130% of Motor Full Load Current.
- Class 10 is faster than Class 20 and Class 30 over Load Relay.
Size of over Load Relay:
|
Size |
Amp Capacity |
|
S00 |
0.1 To 0.4 |
|
0.4 To 0.6 |
|
|
1.6 To 6 |
|
|
3 To 12 |
|
|
S0
|
3 To 12 |
|
6 To 25 |
|
|
S2 |
6 To 25 |
|
13 To 50 |
|
|
S3 |
13 To 50 |
|
25 To 100 |
|
|
S6 |
50 To 200 |
|
S10 & S12 |
55 To 250 |
|
200 To 540 |
|
|
300 To 63 |
Contactor Coil:
| Coil Voltage (40 To 50 Hz) | Suffix |
| 24V | T |
| 48V | W |
| 110V To 127V | A |
| 220V To 240V | B |
| 277V | H |
| 380V To 415V | L |
Type of Contactor for Starter:
|
Contactor |
Application |
|
AC1 |
Non-Inductive or Slightly Inductive ,Resistive Load |
|
AC2 |
Slip Ring Motor |
|
AC3 |
Squirrel Cage Motor |
|
AC4 |
Rapid Start / Stop |
|
AC5a |
Switching of Electrical Discharge Lamp |
|
AC5b |
Switching of Electrical Incandescent Lamp |
|
AC6a |
Switching of Transformer |
|
AC6b |
Switching of Capacitor Bank |
|
AC7a |
Slightly Inductive Load in Household or same type load |
|
AC7b |
Motor Load in Household Application |
|
AC8a |
Hermetic refrigerant Compressor Motor with Manual O/L Reset |
|
AC8b |
Hermetic refrigerant Compressor Motor with Auto O/L Reset |
|
AC12 |
Control of Restive Load and Solid State Load with optocoupler Isolation |
|
AC13 |
Control of Restive Load and Solid State with T/C Isolation |
|
AC14 |
Control of Small Electro Magnetic Load ( <72VA) |
|
AC15 |
Control of Small Electro Magnetic Load ( >72VA) |
Making and Breaking Capacity of Contactor:
| Contactor | Making Capacity(Amp) | Breaking Capacity (Amp) |
| AC1 | 1.5 X motor rated current | 1.5 X motor rated current |
| AC2 | 4 X motor rated current | 4 X motor rated current |
| AC3 | 10 X motor rated current | 8 X motor rated current |
| AC4 | 12 X motor rated current | 10 X motor rated current |
| AC5a | 3 X motor rated current | 3 X motor rated current |
| AC5b | 1.5 X motor rated current | 1.5 X motor rated current |
| AC6a | 12 X motor rated current | 10 X motor rated current |
| AC6b | 12 X motor rated current | 10 X motor rated current |
| AC7a | 1.5 X motor rated current | 1.5 X motor rated current |
| AC7b | 8 X motor rated current | 8 X motor rated current |
| AC8a | 6 X motor rated current | 6 X motor rated current |
| AC8b | 6 X motor rated current | 6 X motor rated current |
| AC12 | ||
| AC13 | 10 X motor rated current | 1.1 X motor rated current |
| AC14 | 6 X motor rated current | 6 X motor rated current |
| AC15 | 10 X motor rated current | 10 X motor rated current |
Contactor Status:
| Contactor Status | Continuity Between Pins (N/C) | Non Continuity Between Pins (N/O) |
|
Power Not Applied |
32 and 33 |
21 and 22 |
|
11 and 12 |
||
|
A1 and A2 |
||
|
B1 and B2 |
||
|
Power Applied |
21 and 22 |
32 and 33
|
|
11 and 12 |
||
|
A1 and A2 |
||
|
B1 and B2 |
Main Circuit Voltage of O/L Relay & Contactor:
- A.C= 240V,415V
- D.C=230V,460V,600V
Contactor’s Coil Voltage:
- A.C= 40V,220V,240V,415V
- D.C=24V(For PLC),110V,230V,460V
Rated Current of Contactor: (Thermal and Intermediate Duty):
- A.C= 6,10,16,25,63,100,160,200,315,400,630,800 Amp
- D.C= 16,20,80,160,315,1250,8000 Amp.
|
Contactor / Relay Setting / Fuse / Cable for DOL STARTER |
||||||||
|
H.P |
KW |
FLC |
Contactor Size (Amp) |
Relay setting |
Fuse |
Cable (mm2) |
||
|
Min |
Max |
Cu |
Allu |
|||||
|
0.5 |
0.37 |
1 |
– |
0.8 |
1.17 |
4 |
1 |
1.5 |
|
0.75 |
0.55 |
1.3 |
9 |
1 |
1.5 |
4 |
1 |
1.5 |
|
1 |
0.74 |
1.9 |
9 |
1.6 |
2.3 |
6 |
1.5 |
2.5 |
|
1.5 |
1.11 |
2.6 |
9 |
2 |
3 |
6 |
1.5 |
2.5 |
|
2 |
1.49 |
3.7 |
9 |
2.5 |
3.7 |
10 |
1.5 |
2.5 |
|
3 |
2.2 |
4.8 |
9 |
4 |
5.9 |
16 |
1.5 |
2.5 |
|
5 |
3.73 |
7.8 |
9 |
6.3 |
9.4 |
20 |
1.5 |
2.5 |
|
7 |
5.22 |
11.2 |
12 |
8 |
11.7 |
25 |
2.5 |
4 |
|
10 |
7.46 |
16 |
16 |
12.5 |
18.7 |
25 |
4 |
6 |
|
12.5 |
9.32 |
19 |
32 |
16 |
23.4 |
32 |
4 |
6 |
|
15 |
11.19 |
20.8 |
32 |
16 |
23.4 |
50 |
6 |
10 |
|
20 |
14.92 |
28 |
32 |
20 |
30 |
50 |
6 |
10 |
|
25 |
18.65 |
34 |
38 |
32 |
37.4 |
63 |
10 |
16 |
|
30 |
22.38 |
40 |
45 |
32 |
47 |
80 |
16 |
25 |
|
40 |
29.84 |
53 |
63 |
50 |
59 |
100 |
25 |
35 |
|
50 |
37.3 |
65 |
70 |
57 |
65.5 |
125 |
25 |
50 |
|
60 |
44.76 |
78 |
85 |
70 |
88.9 |
125 |
25 |
50 |
|
75 |
55.95 |
96 |
110 |
85 |
98.2 |
160 |
50 |
70 |
|
100 |
74.6 |
131 |
140 |
115 |
168 |
200 |
70 |
95 |
|
125 |
93.25 |
156 |
170 |
115 |
168 |
250 |
120 |
150 |
|
150 |
111.9 |
189 |
205 |
160 |
234 |
315 |
150 |
240 |
|
180 |
134.28 |
227 |
250 |
160 |
234 |
355 |
185 |
300 |
|
215 |
160.39 |
271 |
300 |
200 |
299 |
400 |
– |
– |
|
270 |
201.42 |
339 |
400 |
250 |
374 |
500 |
– |
– |
|
335 |
249.91 |
338 |
475 |
320 |
468 |
500 |
– |
– |
|
Relay Range & Back up Fuse for DOL Starter |
|||||
|
H.P |
KW |
Full Load Current (amp) |
Relay Rang(Amp) |
Back Up Fuse |
|
|
Min |
Max |
||||
|
10 |
7.5 |
13.6 |
13 To 20 |
25 |
50 |
|
12.5 |
9.3 |
17 |
13 To 20 |
25 |
50 |
|
15 |
11.2 |
20 |
20 To 30 |
35 |
80 |
|
20 |
14.9 |
28 |
20 To 30 |
60 |
80 |
|
25 |
18.7 |
35 |
30 To 45 |
60 |
100 |
|
30 |
22.4 |
40 |
30 To 45 |
80 |
100 |
|
35 |
26.1 |
47 |
45 To 63 |
80 |
125 |
|
Relay Range & Back up Fuse for Star / Delta Starter |
|||||
|
H.P |
KW |
Full Load Current (amp) |
Relay Rang(Amp) |
Back Up Fuse |
|
|
Min |
Max |
||||
|
20 |
14.9 |
28 |
13 To 20 |
60 |
60 |
|
25 |
18.7 |
35 |
20 To 30 |
60 |
100 |
|
30 |
22.4 |
40 |
20 To 30 |
60 |
100 |
|
35 |
26.1 |
47 |
20 To 30 |
80 |
100 |
|
40 |
29.8 |
55 |
30 To 35 |
80 |
125 |
|
50 |
37.3 |
66 |
30 To 35 |
100 |
125 |
|
60 |
44.8 |
80 |
45 To 63 |
100 |
160 |
|
75 |
55.95 |
95 |
45 To 63 |
125 |
160 |
JIGNESH PARMAR
thanks sir ji
tis is very usfull for us.
Please provide relay coordination examples ..hand calculations if included and developing curves, selection of relay curves.
Thumb rules or any logic or technic or any hidden knowledge in performing relay coordination studies and settings.
Thanks for your knowledge sharing…you are a real master..
Best Regards,
sir please insist me the contactor size for the star delta stater also…….. and simple hand cluculations….
definitely your sharing valueable knowledge is a great task remembered to be ever for comforting other keep it up good job good contribution wish u more grow to show such a contributon to deliver spreading valueable knowledge.
thanks
TANVEER SHAH
thank you for posting it but it is incomplete knowledge for an engineer . he also deserves to know about various specifications as what is voltage and power factor that you have taken into consideration for making this chart. . please provide some basics so that i can select mccb, contactor . o\l relay. for dol and s\d starter.
kindly provide some information.
THANKS
Thanks for your valuable Suggestion !
To calculate Size of Fuse/MCCB,Cable of Motor Please refer another Post Of this Blog
really great and very helpfull…
To calculate size of fuse, contactor, relay,cable of motor please help us.
Already given in the blog…Please search…
Dear Sir,
Your electrical basic note are very valuable as compare to diamond these notes cover all data which are very important for gaining knowledge of career growing engineers. please help me for understanding how 11kv transmission line enter in the plant , how its connected to the LT panel please help me.
we are using all motor 3ph 200 volt motor. any specification is required. based on current selecting is ok?
I really enjoyed your note and I have learned something better from thanK U…💡