摘要:
Jede Unterbrechereinheit (10,12,14) des Schalters für Mittel- und Hochspannung weist eine Antriebswelle (30), ein bewegtes Schaltkontaktstück (18) und ein dieses mit der Antriebswelle (30) verbindendes Uebertragungsgestänge (38) auf. Alle Unterbrechereinheiten (10,12,14) sind identisch aufgebaut. Auf jeder Antriebswelle (30) sitzt drehfest ein Antriebshebel (40), die über Koppeln (44,46) miteinander verbunden sind. Um ein gestaffeltes Schalten herbeizuführen, sind die Antriebshebel (40) mindestens zweier Unterbrechereinheiten (10,12,14) bezüglich deren Antriebswellen (30) in unterschiedlicher Drehlage angeordnet.
摘要:
A controller for a relay (R) controls the pull-in time of the armature of the relay by controlling the power applied to the relay coil (1). To determine the actual pull-in time, the time of closure of the contacts is sensed (37,39) and the time at which power is applied to the coil (6) is subtracted from it (38). The actual pull-in time (at 40) is then compared (42) with a stored value (at 44) of ideal pull-in time to produce an error signal (46). The error signal corrects (14,13) the level of power applied to the relay coil upon the next actuation of the relay, to make the actual pull-in time approximately equal to the ideal pull-in time. In some embodiments, to control the level of power on the coil, a Grey-code counter samples a duty-cycle register (14) in a microcomputer (4) and produces a train of pulses (at 8) that is filtered to provide a DC control signal. The DC control signal controls the duty cycle of a pulse-width-modulated oscillator that rapidly switches (modulates) the power to the relay coil.
摘要:
A control circuit (17) synchronizes operation of a latching relay (K0) to extend contact life. The relay (K0) is switched using an H-bridge drive circuit (22). The synchronization is done using a two-step delay. The first delay is provided by a phase shifter (35), which delays the timing signals used by a logic controller (20) relative to a zero crossing. The second delay is provided by an adjustable timer circuit (22) including a potentiometer (UR2). The two delays are used so that the latching relay (K0) is tripped at a selectable time coinciding with the second zero crossing after a switching command is received.
摘要:
An electronic control for gas furnaces controls a two speed main blower fan and an induction draft fan based on inputs from a room thermostat, a high limit and an ignition control including a gas valve. The control has a circuit board having a power supply for providing 24 volts DC current source to drive DC relays and a 5 volt DC power source to power a microprocessor. 24 volt AC input signals are coupled to the input ports of the microprocessor through current limiting resistors and to AC ground through pull down resistors. AC ground is also connected to the IRQ port of the microprocessor. The output ports of the microprocessor are connected to a relay driver which in turn is connected to relays for energizing and de-energizing the fans. The control calibrates itself on a continuing periodic basis to read the AC inputs synchronously at the peak of their wave and can switch the relays asynchronously based on the Real Time Clock of the microprocessor or can be switched synchronously by providing a selected delay so that contact engagement and disengagement occurs at or near the zero crossing of the AC line voltage wave form. When used with resistive loads the relays are switched in response to a signal from the microprocessor which is delayed based on the mechanical switching time constant of the relays to provide contact closure and opening at the selected point on the AC line voltage wave form. An alternate embodiment shows a feedback network used to calibrate the specific delay period for each relay upon initialization. When used with inductive loads contact closing can be effected synchronously and contact opening asynchronously.
摘要:
The device is used for the control of an electromagnet of which the coil (L) is connected to an alternating current supply source through a switch (T) controlled by a control circuit. Said control circuit comprises a member for determining the zero voltages of the alternating current (R4, C3, D3, IN1, C4, R6, IN2), a delay element adjusted to obtain a delay time which corresponds to the privileged control angle of the electromagnet and a switching device (FL) controlled by the delay element in order to deliver to the switch (T), following a control order, a control signal retarded by said delay time. The invention applies particularly to contactors and to electrovalves.
摘要:
The relay has contacts (14,16) to control delivery of AC power to a load (20), and includes a sensor (46) mounted for detecting any arc at the relay contacts, and a control circuit (50) which controls the time of subsequent actuation or deactuation of the relay with respect to the AC power supply so that the relay contacts open or close substantially at a zero crossing point of the AC current, so as to minimise relay contact arcing, per EP-AZ-0 349 273. The sensor (46) is fixedly mounted by a bracket (48) on the relay base (43), so that its face is reliably fixed in position close to the contacts. The sensor may comprise an optical sensor (46), or the input end (54) of an optical fibre (58; Figure 3), or a field effect sensor (62; Figure 4), or may be in (96; Figure 6) or beneath (65; Figure 5) the relay base.
摘要:
In a hybrid relay circuit for supplying current to a load with a AC power supply, an electromagnetic relay is provided and the contact thereof is connected in series to the load and the AC power. The electromagnetic relay is driven by a driving circuit in accordance with an input control signal, thereby switching the supply of current to the load.