摘要:
An armature mounted armature speed control system for a brushless repulsion motor of the type including a series of coil switches on the armature for shorting a succession of armature coils and detectors on the armature for operating each of the switches when the armature coil shorted by a switch is at a selected rotational position, the system comprising: a ring counter with sequentially energized output lines for receiving signals in sequence at a rate controlled by the reference frequency of count pules at the input of the counter, means for operating the switches in sequence by the counter created signals to control the speed of the armature at a set point and a selector switch shiftable upon receipt of a shift signal between a first condition with the signals from said counter operating the coil switches and a second condition with the detectors operating the coil switches.
摘要:
A method for controlling the power of a load (1) powered from a source of AC voltage U having a period T using a phase control system, wherein, for a predetermined set power, a sequence of an integer p of elements, where p is greater than 1, is periodically delivered to the load (1), each element, numbered i, of the sequence being characterized by an integer n.sub.i with a half-period T/2 during which the AC voltage U is switched according to a series of different phase angles .alpha..sub.i from .alpha..sub.1 to .alpha..sub.n corresponding to respective durations t.sub.i from t.sub.l to t.sub.n during which the load (1) is cut: off from the power supply. The phase angles .alpha..sub.i of element i and .alpha..sub.i+1 of element i+1 have similar repetitive values so that the mean current is zero over a complete cycle.
摘要:
A brushless repulsion motor in which the rotor carries electronic switch circuits for selectively shorting the rotor windings at appropriate times in its rotational cycle. A non-contact reference signal source on the stator enables the electronic circuitry to operate as desired. The disclosed motor arrangements are useful as substitutes for conventional brush-type repulsion motors, universal series motors, synchronous motors, servomotors and stepping motors.
摘要:
A brushless repulsion motor in which the rotor carries electronic switch circuits for selectively shorting the rotor windings at appropriate times in its rotational cycle. A non-contact reference signal source on the stator enables the electronic circuitry to operate as desired. The disclosed motor arrangements are useful as substitutes for conventional brush-type repulsion motors, universal series motors, synchronous motors, servomotors and stepping motors.
摘要:
An apparatus for controlling a three-phase inverter supplying the a.c. motor of an elevator, the inverter having a power stage implemented with semiconductor switches, and the apparatus comprising an electronic control unit for producing a velocity reference value and a tachometer generator for producing an actual velocity value, voltage measuring elements for measuring a.c. voltages at the inverter output, and pulse width modulators and drivers for controlling the semiconductor switches in the inverter's power stage with control signals derived from the pulse width modulators. With the apparatus of the invention, fast control of the control voltage is achieved. Moreover, simpler voltage measuring elements may be used instead of current measuring elements. The apparatus of the invention comprises a speed regulator for producing a rotor current frequency and the frequencies of first reference voltages from the actual velocity value and the velocity reference value, a curve calculator for producing the amplitude of the reference voltages from the rotor current frequency and the frequency of the reference voltages, a three-phase oscillator for producing second reference voltages from the frequency and amplitude of the first reference voltages, and voltage regulators for producing control voltages for the pulse width modulators from additional reference voltages obtained from the second reference voltages and the actual value voltages obtained at the inverter output.
摘要:
Circuit arrangements to improve the performance of motor speed control circuits using electronic switching on an AC waveform where it is desired to remotely control the electronic switch without either load current or the load waveforms being present at the controlling element. The voltage across the switching device, during the time it is off, is rectified, and used as the charging voltage for the phase firing circuit, with a resistor capacitor timing network determining the firing of the switching device when the capacitor voltage reaches a predetermined value.
摘要:
Disclosed is an apparatus for controlling the rotational speed of an electric motor based upon the load encountered by the electric motor. A load sensor provides a voltage level based upon the operating load of the electric motor and accumulates this voltage in accordance with the cycle of the alternating current supplied to the motor. If during a cycle of the alternating current, the voltage exceeds a predetermined level, a transistor will be biassed into conduction, said transistor turning off a thyristor and preventing any further conduction of the thyristor during that cycle of the alternating current. Thus the duty cycle of the thyristor determines the total amount of current supplied to the electric motor and this current level determines the rotational rpm of the motor.
摘要:
A full wave motor control circuit is provided which utilizes a phase fired SCR to control the flow of current through the motor windings. Just before the end of each cycle, the charging capacitor which is connected across the gate and cathode of the SCR is discharged and the effective holding current level of the SCR is raised to insure SCR turn off.
摘要:
A motor control circuit is provided for an appliance or the like of the type utilizing a speed adjustment device that controls an adjustable centrifugally controlled governor device. The governor includes a switch contact arrangement which is connected in the triggering circuit of a power switching device, a TRIAC for example, for selectively connecting the motor of the appliance to the power source connections. The switch contacts of the governor device open and close as the rotational speed of the motor increases and decreases respectively from the speed selected on the speed adjustment device. A variable impedance element mechanically coupled to and adjusted by the speed adjustment device is also provided in the triggering circuit of the power switching device in series with the governor switch contacts to vary the triggering of the power switching device as the speed setting is varied. Thus, a variable speed versus motor supply voltage characteristic is provided when the governor contacts are closed. A wider range of stable speed control is provided than is obtained with a governor device alone. Low speed cogging and high speed hunting problems are also minimized. The variable impedance element in various embodiments is arranged to provide a variable impedance characteristic over a portion of the speed adjustment device range and a fixed impedance over the remainder of the range.
摘要:
Variable-speed electric motor drive includes a universal motor having a power supply line wherein a thyristor is connected and operated in a phase gating circuit, a firing circuit for the thyristor, a variable first resistance connected to the firing circuit of the thyristor for varying the rotary speed of the motor, and a temperature-dependent second resistance associated with the firing circuit and thermally coupled to the thyristor.