Fig. 2,428.—Diagram of connections of General Electric direct current (form S) voltage regulator, for 125, 250, and 550 volts. The range of voltage is given in the following table:
| Regulator | Range of voltage | ||||
|---|---|---|---|---|---|
| 16 | 17 | 18 | 19 | 20 | |
| 125 | 105 | 110 | 115 | 120 | 125 |
| 250 | 210 | 220 | 230 | 240 | 250 |
| 550 | 550 | ||||
Ans. Vibration or chattering at the contacts of both relays and tendency of the movable contact arm of the primary relay to hug closer to one of the stationary contact points than to the other, thereby operating too often.
Ques. What causes vibration or chattering at the contacts?
Ans. This is due to the voltage frequently approximating the value required for closing a contact, thereby causing the contact points to barely touch and make several poor contacts in succession.
Ques. What objectionable action is produced by vibration at the contacts?
Ans. Arcing, burning and pitting of the contacts, even when alloys of the rarer metals are used, such as those of the platinum group, having extreme hardness and high melting points.
Fig. 2,429.—Diagram of connections of automatic induction regulator and auxiliary apparatus on single phase circuit.