Standby control for electromagnet
First Claim
1. Apparatus for charging and controlling a standby battery in circuitry receiving AC from a main power source, the circuitry including a power circuit and a control circuit, the power circuit including an electromagnet and the battery, comprising,a power rectifier in the power circuit for rectifying AC from the main source to DC,circuit means in the power circuit connecting the battery in parallel with the rectified DC from the main source and in parallel with the electromagnet,back-to-back SCRs in the power circuit controlling the AC to the power rectifier,a control transformer having a primary connected with the AC in the main source and a secondary in the control circuity,a control rectifier connected with the secondary of the control transformer,a pulse transformer having a primary connected with the output of the control rectifier and secondaries connected with respective SCR'"'"'s for energizing the battery, andfirst control means for measuring the current in the electromagnet and controlling the pulse transformer and thereby the SCR'"'"'s and the current to the electromagnet,the battery remaining in operable connection with the electromagnet upon interruption for the main AC source.
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Accused Products
Abstract
A power circuit has an AC portion connected with a main AC source and a DC source portion including a magnet and battery constantly connected in parallel. Back-to-back SCRs control a rectifier between the AC and DC portions. A DC control circuit includes a pulse transformer controlled by a capacitor charged by DC pulses at a rate controlled by a manual setting. Upon discharge, the capacitor energizes the pulse transformer and thus turns ON the magnet and battery. Upon disconnecting the load, the battery is automatically charged at about 4 amperes. Safe and unsafe indicators are connected across the battery, and upon drop of battery charge, digital control elements in the control circuit control those indicators to correspondingly indicate safe or unsafe conditions.
14 Citations
18 Claims
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1. Apparatus for charging and controlling a standby battery in circuitry receiving AC from a main power source, the circuitry including a power circuit and a control circuit, the power circuit including an electromagnet and the battery, comprising,
a power rectifier in the power circuit for rectifying AC from the main source to DC, circuit means in the power circuit connecting the battery in parallel with the rectified DC from the main source and in parallel with the electromagnet, back-to-back SCRs in the power circuit controlling the AC to the power rectifier, a control transformer having a primary connected with the AC in the main source and a secondary in the control circuity, a control rectifier connected with the secondary of the control transformer, a pulse transformer having a primary connected with the output of the control rectifier and secondaries connected with respective SCR'"'"'s for energizing the battery, and first control means for measuring the current in the electromagnet and controlling the pulse transformer and thereby the SCR'"'"'s and the current to the electromagnet, the battery remaining in operable connection with the electromagnet upon interruption for the main AC source.
Specification