Power connect safety and connection interlock

• US 5,099,187 A
• Filed: 03/21/1990
• Issued: 03/24/1992
• Est. Priority Date: 03/21/1990
• Status: Expired due to Fees

• Current Assignee: California Institute of Technology
• Original Assignee: California Institute of Technology
• Inventors: Rippel, Wally E.
• Primary Examiner(s): Pellinen, A. D.
• Assistant Examiner(s): Osborn, David
• Application Number:
  US07/497,082
• Time in Patent Office: 734 Days
• Field of Search: 307/10.7, 307/31, 307/38, 307/39, 307/246, 307/326-328, 307/100, 307/109, 307/130, 307/135, 307/147, 320/1, 361/1, 361/15-17, 361/58, 361/160, 361/170, 361/187, 361/188, 361/225, 323/908, 439/133, 439/135, 439/136, 439/305, 439/924
• US Class Current: 320/166
• CPC Class Codes: H01R 13/707 interlocked with contact members or counterpart
• CPC Class Codes: H02H 9/001 limiting speed of change of electric quantities, e.g. soft switching on or off progressive control of electronic switches for eliminating interferences H03K17/16

Abstract

A power connect safety and connection interlock system is shown for use with inverters and other DC loads (16) which include capacitor filter banks (14) at their DC inputs. A safety circuit (20) operates a spring (26) biased, solenoid (22) driven mechanical connection interference (24) which prevents mating and therefore electrical connection between the power contactor halves (11, 13) of the main power contacts (12) until the capacitor bank is safely precharged through auxiliary contacts (18). When the DC load (16) is shut down, the capacitor bank (14) is automatically discharged through a discharging power resistor (66) by a MOSFET transistor (60) through a discharging power resistor (66) only when both the main power contacts and auxiliary contacts are disconnected.

Claims

1. A power interconnection system for connecting a DC power source to a capacitor bank at the input of a DC load, comprising:

a pair of power contact halves connectable between the DC power source and the capacitor bank;

a safety circuit for precharging the capacitor bank; and

mechanical interference responsive to the safety circuit for selectively preventing electrical connection through the power contact halves until the capacitor bank has been safely precharged.

2. The power interconnection system claimed in claim 1 further comprising:

spring means for urging the mechanical interference into a first position preventing electrical connection through the contact halves, and

solenoid means responsive to the safety circuit for urging the mechanical interference into a second position permitting electrical connection through the power contact halves when the capacitor bank has been safely precharged.

3. The power interconnection system claimed in claim 2 wherein the safety circuit urges the mechanical interference into the second position when the charge on the capacitor bank reaches a predetermined level.

4. The power interconnection system claimed in claim 2 wherein the safety circuit further comprises:

auxiliary contact for connecting the safety circuit to the DC power source;

a discharging circuit for selectively discharging the capacitor bank only when both the power contact halves and the auxiliary contacts are disconnected.

5. A method of connecting a DC power source to a capacitor bank at the input of a DC load, comprising the steps of:

connecting a safety circuit to the DC power source for precharging the capacitor bank; and

mechanically interfering with the mating of a pair of power contact halves connectable between the DC power source and the capacitor bank for selectively preventing electrical connection through the power contact halves until the capacitor bank has been safely precharged.

6. The method claimed in claim 5 wherein the mechanical interference steps further comprise the step of:

removing the mechanical interference when the capacitor bank has been safely precharged.

7. The method claimed in claim 6 wherein the mechanical interference is removed when the charge on the capacitor bank reaches a predetermined level.

8. The method claimed in claim 6 wherein the safety circuit step further comprises the steps of:

connecting the safety circuit to the DC power source through auxiliary contacts; and

discharging the capacitor bank only when both the power contact halves and the auxiliary contacts are disconnected.