| 摘要 |
<p>PURPOSE:To prevent an overdischarge so as to improve a cycle life of a battery by turning off an automatic main switch of a power supply circuit when voltage or a discharge current reaches a preset value or less by decreasing battery capacity during work. CONSTITUTION:When a work manual switch 5 is turned on, a current is allowed to flow in a DC motor 2, and a cutter blade 1 of a work device, for instance, mower, connected to the DC motor 2, is rotated to perform grass or lawn mowing work. When the DC motor 2 is continued rotated by performing this work for a long time, capacity of a battery 3 is decreased, and battery voltage is decreased. The battery voltage, when it is decreased to preset voltage or less for holding excitation of an electromagnetic solenoid 10, is detected by a Zener diode 7, and the electromagnetic solenoid 10 is deenergized to turn off an automatic main switch 6 which is a relay contact. In this way, the battery 3 can be charged in a condition that a fixed amount of discharge capacity is left.</p> |
