Industry Patents
Patent: 6175220
Short-Circuit Protection for Forward-Phase-Control AC power Controller
(Click image for PDF of full patent)
| Patent Number: |
6175220 |
| Title: |
Short-Circuit Protection for Forward-Phase-Control AC power Controller |
| Abstract: |
A thyristor-based forward phase control (FPC) system for controlling the
power delivered to a load from an AC power source employs a short-circuit
test cycle to protect the thyristor from damage. Upon activation of the
FPC system, the thyristor is triggered at a phase less than one-twelfth
cycle before a zero crossing so that, if there is a short, the resulting
peak current will be insufficient to damage the thyristor but will exceed
a predetermined threshold current corresponding to a repetitive overload
current. If during the test cycle, the threshold current value is crossed,
the FPC system does not trigger the thyristor again and does indicate that
a short exists. The threshold current value is selected to correspond to
the thyristor's steady-state load rating. If it is exceeded during normal
(including warm-up and request-based) operation, steps can be taken to
address an overload condition. Accordingly, the same circuitry used for
general overload protection can be used as well for short-circuit
protection.
|
| Country of Issue: |
US |
| First Named Inventor: |
Billig, Carlson |
| Assignee: |
Power Innovations |
| Continuation or Divisional of: |
|
| International Classification: |
G05F 1/10 |
| US Classification: |
323/239 |
| Issue Date: |
01-16-2001 |
| Filing Date: |
10-22-1999 |
| Application : |
09/425504 |
| Notes: |
|
| Link to Patent at freepatentsonline.com: |
6175220 at Freepatentsonline |
| Link to World Patent Family1: |
World Patent Family at European Patent Office |
| Link to Google Patents1: |
6175220 at Google Patents |
1. The Google Patents and World Patent Family links will likely not work until a few weeks
after the patent has issued - they take a while to get new patents in their systems.
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