Volume 8 – Mechanical and Electrical Services - Malaysia Geoportal

Chapter 7 ELECTRICAL SERVICES
Table 7.1 NEMA Code for Start kVA/HP for 3-phase Squirrel Cage Motors
Remarks : If Start kVA is not known, use the higher value.
Code StartkVA/HP Mostly Used On
A 0 – 3.15
B 3.15 – 3.55 Normal Torque, Low Starting Current
C 3.55 – 4.00 High Torque, Low Starting Current
D 4.00 – 4.50 High Torque, High Slip
E 4.50 – 5.0
F 5.0 – 5.6 >15 Hp
G 5.6 – 6.3 10Hp
H 6.3 – 7.1 < 7.5 HP but > 5 HP
J 7.1 – 8.0 3 HP
K 8.0 – 9.0 > 1.5 HP but < 2 HP
L 9.0 – 10.0 1 HP
M 10.0 – 11.2 < 1HP
etc
Table 7.2 Reduced Voltage Assistance Starting from NEMA Code
Code Starting Method Starting kVA (%) Starting Torque (%)
C Reactor or Resistance 80% Tap 80 64
D Start - Delta 33 33
E Half Winding 65 50
The calculation shall be based on NEMA standard for estimating the starting KVA for the water pump
motor. Sample of calculation shall be tabled in Appendix 7E
7.3.7.3 Maintenance
Maintenance can be divided into:-
a) Correction maintenance
- All maintenance performed in order to correct to failure
b) Preventive maintenance
- Direct preventive maintenance performed in order to prevent failure from accuring (eg.
Cleaning lubrication at regular intervals).
- Indirect Preventive maintenance or condition monitoring are all measures taken to discover
faults before they result in operational disturbances or unnecessary damage (eg.
Performance monitoring and testing)
March 2009 7-13