Drive device for single-phase series commutator motor

Abstract

A drive device (1) of the present invention includes a pair of drive switches (12, 14), a first diode (D1), a switching element (16), a current detection unit (R1, 18), a capacitor (C1), a second diode (D2), and a current control unit (20). The first diode (D1), the switching element (16), and the current detection unit (R1, 18) are arranged, in this order from one end of an armature (4) in a motor (2), on a braking current path that is formed of the armature (4) and a field winding (6, 8) in the motor (2) when the pair of drive switches (12, 14) is in a brake position. The second diode (D2) is adapted to keep allowing a braking current to flow through the field winding (6, 8) when the switching element (16) is in an off-state by directly connecting a partial path between the switching element (16) and the current detection unit (R1, 18) on the braking current path and the other end of the armature (4).

Description

technical field [0001] The invention relates to a drive device for a single-phase series excitation commutator motor. Background technique [0002] (Outline of single-phase series commutator motor) [0003] A single-phase series commutator motor can be driven rotationally in both DC and AC power sources, and is called an AC-DC dual-purpose motor. Since it can be rotated at a high speed, the influence of the power supply frequency is small, and it can be manufactured at a low cost, it is better utilized for power tools using an AC power supply. [0004] In addition, the single-phase series-excited commutator motor has an armature winding and a field winding connected in series, and when a power supply is connected there, torque is generated and rotational drive is performed. [0005] The characteristic structure of the single-phase series commutator motor is that the generated torque is always fixed in one direction, regardless of the polarity of the AC power supply or the ...

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Problems solved by technology

[0020] However, in the device proposed above, when the braking current reaches a certain upper limit, the both ends of the field winding are connected to the resistor for current consumption, so there is a possibility that the resistor itself will be damaged due to the current flowing through the resistor. problems like fever

[0021] Therefore, in order to put the device proposed above into practical use, it is necessary to implement heat dissipation measures for dissipating the heat generated by the resistor as follows, for example, providing a heat sink for heat dissipation on the resistor, or using a large Resistors, which have the problem of increasing the size of the motor and the electric tool constructed using the motor

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