| 摘要 |
An alternator for use in a mine working is enclosed within a flame- proof housing (30) and with a source of electrical power (15) inside the housing. The excitation current is controlled at the alternator to avoid excessive output current and output terminals 21 are isolated by circuit 16 until alternator voltage is normal, power source 15 providing excitator current until normal voltage is reached once residual rotor magnetism generates a small initial voltage in circuit 16 to permit power source current to flow. <IMAGE> |
