21
2-4-2 Application of AC4 (Application of Cases Including Inching and Plugging)
In equipment and machinery which include inching and plugging (negative-phase braking), make and break of large
starting rush current of the motor will occur frequently. Category AC4 is applied for such usage. Application of AC4
is shown in Tables 1 and 2 in page 12 of the catalogue.
2-4-3 Application of AC1 (Application to AC Resistance Load)
Category AC1 is applied when using a resistance load which does not necessitate consideration of rush current at
starting such as the incandescent light, electric heater, etc.
Application of AC1 is shown in Table 3 in page 13 of the catalogue.
2-4-4 Application of DC Load
The breaking category of DC load becomes far more severe in comparison with AC load. However, contactor can be
applied as shown in Table 4 in page 13 of the catalogue.
2-4-5 Application for Star-Delta Starters
Delta motor is star-connected during starting, and reduces starting current and torque to one-third of full-voltage
starting values.
(1) Loads applied to star-delta starters and electrical endurance of starter
Table 15. Load and electrical endurance
Load Example of load Electrical endurance
unloaded start machine tools, lathe, general industrial machines, etc. 500,000
square torque vortex pumps, turbine pumps, fans, blowers,
dehydrators, centrifugal dehydrators, etc.
50,000
(2) Kinds of star-delta starters
2 Contactors method
Phase-current detecting method
3 Contactors method
Star-delta starter
2 Contactors method
Line-current detecting method
3 Contactors method
(3) Component number explanation and symbol explanation
Table 16.
No. Name Mark Name
2 Timer IM Motor
6 Contactor for star BS Push button (start)
22 Circuit breaker (FFB) BSS Push button (stop)
42 Contactor for delta a Normally open contact
49 Thermal overload relay b Normally closed contact
52 Contactor for insulation EF Fuse
To Next Page
Loading...
