Hello Guest it is October 21, 2019, 04:55:11 PM

Author Topic: power supply tolerance  (Read 2583 times)

0 Members and 1 Guest are viewing this topic.

power supply tolerance
« on: March 06, 2012, 10:25:00 AM »
just bought a second hand multi output power supply from ebay

but there is quite a bit of difference between req'd output and

actual measured

req'd voltage (dc)   actual measured voltage (dc)

+12v                     +14.06v
+12v                     +13.79v
+24v                     +27.8v
+50v                     +48.5v
-12v                       -13.7v
+5v                       +5.2v

will this level of overvoltage damage breakout boards etc?

what is the normal tolerance on power supplies

cheers George

Offline Hood

*
  •  25,856 25,856
  • Carnoustie, Scotland
    • View Profile
Re: power supply tolerance
« Reply #1 on: March 06, 2012, 11:18:18 AM »
Are you checking the voltages with a load on the outputs? It will likely fall down nearer to specs when there is a load.
Hood
Re: power supply tolerance
« Reply #2 on: March 06, 2012, 11:43:37 AM »
Hi Hood

no I was just testing across terminals?

the power outputs are

+12v @ 12A
-12v  @ 2A
+24v  @ 3A
+50v  @ 10A
+5v   @ 3A

what would you recommend for a load to test?

(sorry for basic question but not electrical)

cheers  G
Re: power supply tolerance
« Reply #3 on: March 06, 2012, 11:54:46 AM »
What you have is clearly an unregulated supply, which will reach the rated voltage only at, or near, full load.  Most electronic devices are spec'd at +/- either 5% or 10% on supply voltage, and you are well over that on all but the 5V output.  In particular, most ICs are spec'd for no more than +/-10%, and are VERY likely to be damaged if this is exceeded.  I would not use that supply to directly power any electronics, without knowing that they can tolerate the over-voltage.

Either get another supply, or add regulators to that one (and this is not really practical, or cost-effective at those current levels....).

Regards,
Ray L.
Regards,
Ray L.
Re: power supply tolerance
« Reply #4 on: March 06, 2012, 01:38:02 PM »
Ok many thanks for the help

George
Re: power supply tolerance
« Reply #5 on: March 07, 2012, 06:44:44 AM »
can someone tell me

is a linear power supply the same as a regulated power supply

cheers G
Re: power supply tolerance
« Reply #6 on: March 07, 2012, 10:05:59 AM »
"is a linear power supply the same as a regulated power supply" - absolutely not.  A regulated supply may, or may not, be linear, and a linear supply may, or may not, be regulated.  "Linear" indicates it is not a switching power supply, but says nothing about whether or not it is regulated.

Regards,
Ray L.
Regards,
Ray L.