Astron REALLY hot

[zoopa_man]

I just got a new 156w peltier (15volt 16amp) and a variable Astron VS-20M power supply to run the pelt off of. The amp meter goes to 25amps and the volts to 15volts

When I started off I dialed the power supply to 15 volts and 16 amps and threw my Multi meter on to check that. Yup, I got a steady 15volt reading. So I knew that the pelt specs would be met by this power supply. So I hooked up my Pelt and gave it the 15v 16a just like the specs for the pelt said. My temps dropped to 4C and i said cool..booted my system and played around. After 4 hours of testing out my new rig I put my hand on top of my Astron Power Supply to see if it was heating up and I just about lost my hand ! The surface was scorching hot !

I thought it could be because it was a little stressed form running a heavy load. So I dialed down my Amps to 12 amps and left it at 15volts. The surface doesn’t burn my hand now but it's still pretty hot. The power supply should be able to handle 15 volts and 25amps...Why is this pelt making it heat up so much ?

Another thing I've noticed while playing with my variable volt and amp Astron is that when I first turn on the power supply the VU meters read about 10amps 12volts and the voltage slowly rises to 15volts as the power supply heats up over a course of about 15 minutes. I find that strange. I don't understand it.

The other weird thing I’ve discovered is that If I turn the amp rheostat all the way up to start I get the 10a 12v Readings. after The power supply warms up If I turn down the amp rheo my voltage and amps actually goes up for a little then I hit a point where both V and A falls off drastically. I don't understand why this happens either.

Can anyone help me on my 3 questions about my Astron Power supply ? Why is it so hot ? should I add a fan ?

How come it takes so long to get 15v out of my power supply ?

Why do the volts and amps go up when I turn down the amp rheostat after the power supply heats up ?

 

[RangerJoe]

<~~~~~ clueless, sorry i cant help though...you MIGHT try adding another fan, but if its scorching hot, a fan wont do much

 

[Bender]

Very strange sounding. My Astron RS-50 gets a little warm but not hot with a 226 watt 15.2v 24 amp peltier. I bet it would get hot if I used the maximum amperage at 15v. I'll have to monitor voltage from mine one of these days. Even if the Astron is very hot a slow moving 80mm fan will do it a lot of good since it has no active cooling. Colin might know if this is normal since he has a adjustable voltage Astron he used for dual pelts.

 

[Lt. Max]

i dunno, but as much as i kno PSU r designed for up to 12 volts... not a good idea to put out more me thinks..,

 

[Colin]

I can tell you that the heatsinks on my VLS-35M get too hot to touch when running two 120 watt pelts. You may want to shoot Astron and email regarding your other questions.

 

[zoopa_man]

Ok. I'll write them a letter an post here what they say so everyone can see what they have to say. Info is always useful to some one else too. hehe Let you all know when i get an answer.

 

[zoopa_man]

Well....got a reply back form astron finally. Here's what the astron VS-20m specs on their site say...

MODEL Duty (Amps) (Amps) H x W x D Wt. (lbs.)
@13.8VDC @10VDC @5VDC @13.8VDC
VS-12M 9 5 2 12 4 1/2 x 8 x 9 13
VS-20M 16 9 4 20 5 x 9 x 10 1/2 20
VS-35M 25 15 7 35 5 x 11 x 11 29
VS-50M 37 22 10 50 6 x 13 3/4 x 11 46
VS-70M 57 34 16 70 6 x 13 3/4 x 12 1/8 48


And here is what they said in their email :


THE VS-20M POWER SUPPLY IS TOO SMALL TO RUN YOUR LOAD.AT 15VOLTS THE VS-20M IS GOOD FOR 10 AMPS.
JANE


So my solution has been to keep the voltage down to 12 or 13 volts and keep the amps down to 10amps. It only seems to have a bout a 1 or 2 degree difference in temps on the pelter's cooling effectiveness. And at that load the power supply frame doesn’t get extremely hot..but the heat sinks on the back are still pretty hot. I think what i'm going to do is rig up a large 120mm fan to mount on the top of my power supply to draw hot air out the top of the case and put some slots on the sides near the bottom so cool air can be drawn in there. That I think will help solve my problem of an Overheating Astron Power supply.

I still have no clue about the answer to my other two questions of why the amps / volts start off low and progressively go up as I run the power supply. Or why I can get them to go up when i turn down the rheostats that control the volts / amps. I may have to talk to the electronics professor at my college to see if he can help me out and get me pointed in the right direction. I'd hate to drop the bones for a larger power supply, there just too darn expensive to just get a bigger one. Thanks for all your help. I'll keep you all updated.