Direction: In an EDM process using RC relaxation circuit, a 12 mm diameter, through hole is made in a steel plate of 50 mm thickness using a graphite tool and kerosene as dielectric. Assume discharge time to be negligible. Machining is carried out under the following conditions.
Resistance = 40 ohms
Capacitance = 20 μF
Supply voltage = 220 V
Discharge voltage = 110 V
-
The time for one cycle, in milliseconds, is
-
- 0.55
- 0.32
- 0.89
- 0.24
Correct Option: A
Cycle time:
| Tc = R.C.In |  |  | Vs – Vd |
| = 40 × 20 × 10-6 × In | | | 220 – 110 |
Tc = .55 miliseconds.
