Electrical Motor Quick Reference
September 1, 2013 10 Comments
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 |
JIGNESH PARMAR
Hello Sir,
I am a huge fan of yours. I recently ran into your blog and have been hooked since. Your blog contains all vital information that an electrical engineer, like me, needs to know and I thank you for the pain that you took to make it available for everyone. I have one request, if its not too much for you, can you please explain relay coordination in an industry or substation using an example?
Thank you and keep up the good work. We’ll always look up to you for inspiration.
Hello Sir,
Thanks for your great support in Electrical ,please let me know the Magnetizing current in a Transformer and basic tests to be conducted before charging the Transformer ,and Standard Tolerances to be followed for Transformer Selection ,and General Transformer Erection Procedure, and Pre Commissioning Checks,Check List for Smother Maintenance.
Jignesh,
Thanks a lot for your Blog. I have a question for you:
What is the impact of modeling or not modeling the static wire in a Transmission, Distribution line? I am doing a model for a transmission line and I want to know how much details I need to have to have reasonable results.
Regards
Hello Sir,
could you say Which Standards You are used in above All the details.
Thanking you,
P.Ashokan
Chennai
why in a.c power cable like to delta shape? please tel me sir.
thanking you,
Mintu kr. pandit
Howrah/ W.B
why in a.c power cable like to delta shape? please tel me sir,
thanking you
mintu kr. pandit
Howrah / W.B
How rating of tertiary winding winding is formulated, calculated?
Hai Sir,
Good Day
In above note its mentioned AC-6b type duty contactor is used for transformer switching. But according to my knowledge it’s for switching of capacitor banks. Please confirm this.
Hai Sir,
Good Day
In above note its mentioned AC-6b type duty contactor is used for transformer switching. But according to my knowledge it’s for switching of capacitor banks. Please confirm this.
Hi Sir,
Do you have the document how to do tan delta test using Megger D4000?