Hello group,
My company is building a laser power supply that is to be certified using UL
1950. This application is new territory for us.
The normal operating voltage for the laser is 110 Vdc; however, there is a
starting pulse of approximately 4 kV. This starting pulse is less than 1
micro-second in duration and is repeated every 1 second until the laser
lights. The laser voltage is not isolated from the mains. My questions
have to do with how to determine the spacing requirements.
1) Since the laser voltage is not isolated from mains, should we use Table 3
(primary circuits) to determine clearances?
2) If the laser is functioning properly, the 4 kV starting pulse is only
repeated once or twice and then the laser lights. There would have to be
something wrong with the laser in order for the starting pulse to keep
recurring. Wouldn't this be considered an abnormal condition? And if so,
wouldn't the spacings be based on just the 110 Vdc operating voltage?
(i.e., the starting pulse would not normally be a repetitive peak)
3) If we need to consider the starting pulse as a repetitive peak, Table 4
does not cover this because it stops at 1,300 V. Can we extrapolate the
values in this table?
4) Would the creepage distance be based on the normal operating voltage (110
Vdc), disregarding the starting pulse?
Thanks for any help that you can offer!
Best Regards,
Jeff Jenkins
Advanced Energy Industries, Inc.
Fort Collins, CO USA
-------------------------------------------
This message is from the IEEE EMC Society Product Safety
Technical Committee emc-pstc discussion list.
To cancel your subscription, send mail to:
[email protected]
with the single line:
unsubscribe emc-pstc
For help, send mail to the list administrators:
Jim Bacher: [email protected]
Michael Garretson: [email protected]
For policy questions, send mail to:
Richard Nute: [email protected]
