Electrical Motor Quick Reference

ELECTRICAL MOTOR QUICK REFERENCE

STANDARD SIZE OF MOTOR (HP):

Electrical Motor (HP)

1,1.5,2,3,5,7.5,10,15,20,30,40,50,60,75,100,125,150,200,250,300,400,450,500,600,700,

800,900,1000,1250,1250,1500,1750,2000,2250,3000,3500,4000

 APPROXIMATE RPM OF MOTOR

HP

RPM

< 10 HP

750 RPM

10 HP to 30 HP

600 RPM

30 HP to 125 HP

500 RPM

125 HP to 300 HP

375 RPM

 STANDARD SIZE OF MOTOR (HP):

Electrical Motor (HP)

1,1.5,2,3,5,7.5,10,15,20,30,40,50,60,75,100,125,150,200,250,300,400,450,500,600,700,

800,900,1000,1250,1250,1500,1750,2000,2250,3000,3500,4000

 MOTOR LINE VOLTAGE:

Motor (KW)

Line Voltage

< 250 KW

440 V (LV)

150 KW to 3000KW

2.5 KV to 4.1 KV (HV)

200 KW to 3000KW 3.3 KV to 7.2 KV (HV) 1000 KW to 1500KW 6.6 KV to 13.8 KV (HV)

 MOTOR STARTING CURRENT:

Supply

Size of Motor

Max. Starting Current

1 Phase < 1 HP 6 X Motor Full Load Current 1 Phase 1 HP to 10 HP 3 X Motor Full Load Current 3 Phase 10 HP 2 X Motor Full Load Current 3 Phase 10 HP to 15 HP 2 X Motor Full Load Current 3 Phase > 15 HP 1.5 X Motor Full Load Current

MOTOR STARTER:

Starter

HP or KW

Starting Current

Torque

DOL <13 HP(11KW) 7 X Full Load Current Good Star-Delta 13 HP to 48 HP 3 X Full Load Current Poor Auto TC > 48 HP (37 KW) 4 X Full Load Current Good/ Average VSD 0.5 to 1.5 X Full Load Current Excellent Motor > 2.2KW Should not connect direct to supply voltage if it is in Delta winding

MAX. LOCK ROTOR AMP FOR 1 PHASE 230 V MOTOR (NEMA)

HP

Amp

1 HP

45 Amp

1.5 HP

50 Amp

2 HP

65 Amp

3 HP

90 Amp

5 HP

135 Amp

7.5 HP

200 Amp

10 HP

260 Amp

 THREE PHASE MOTOR CODE (NEMA)

HP

Code

<1 HP

L

1.5 to 2.0 HP

L,M

3 HP

K

5 HP

J

7 to 10 HP

H

15 HP

G

 SERVICE FACTOR OF MOTOR:

HP

Synchronous Speed (RPM)

3600 RPM

1800 RPM

1200 RPM

900 RPM

720 RPM

600 RPM

514 RPM

1 HP

1.25

1.15

1.15

1.15

1

1

1

1.5 to 1.25 HP

1.15

1.15

1.15

1.15

1.15

1.15

1.15

150 HP

1.15

1.15

1.15

1.15

1.15

1.15

1

200 HP

1.15

1.15

1.15

1.15

1.15

1

1

200 HP

1

1.15

1

1

1

1

1

 TYPE OF CONTACTOR:

Type

Application

AC1

Non Inductive Load or Slightly Inductive Load

AC2

Slip Ring Motor, Starting, Switching OFF

AC3

Squirrel Cage Motor

AC4,AC5,AC5a, AC5b,AC6a

Rapid Start & Rapid Stop

AC 5a

Auxiliary Control circuit

AC 5b

Electrical discharge Lamp

AC 6a

Electrical Incandescent Lamp

AC 6b

Transformer Switching

AC 7a

Switching of Capacitor Bank

AC 7b

Slightly Inductive Load in Household

AC 5a

Motor Load in Household

AC 8a

Hermetic refrigerant compressor motor with Manual Reset O/L Relay

AC 8b

Hermetic refrigerant compressor motor with Automatic Reset O/L Relay

AC 12

Control of Resistive Load & Solid State Load

AC 13

Control of Resistive Load & Solid State Load with Transformer Isolation

AC 14

Control of small Electro Magnetic Load (<72 VA)

AC 15

Control of Electro Magnetic Load (>72 VA)

 CONTACTOR COIL:

Coil Voltage

Suffix

24 Volt

T

48 Volt

W

110 to 127 Volt

A

220 to 240 Volt

B

277 Volt

H

380 to 415 Volt

L

SIZE OF CAPACITOR FOR P.F CORRECTION:

For Motor

Size of Capacitor = 1/3 Hp of Motor ( 0.12x KW of Motor)

For Transformer

< 315 KVA 5% of KVA Rating 315 KVA to 1000 KVA 6% of KVA Rating >1000 KVA 8% of KVA Rating