Old SunRise Regulated DC Power Supply - RPS3205 - Page 1
Forum section: electronics / general

author: toli
author_rank: Frequent Contributor
timestamp: September 26, 2012, 08:33:37 am
content: Hi Guys,I've actually had this one for a few months already, but decided to post some pictures just for the fun of it.I already have a lab PS which I'm quite happy with. While it isn't a modern one, it fits most of my needs. I've posted some pictures and data about it in the pasthere.However, over time I've noticed sometimes I need more current than what this one could deliver (up to 40V-2A when its set to parallel mode) and started looking for a used PS.Finally, on one of my regular trips to the "junk" store I came across a 2-channel 30V 5A per channel PS. I hooked it up and one of the channels seemed to be working fine while the other was outputting 41.2V no matter where the dials were set. I figured it would be an easy fix, payed about 23$ and took it back homeTook it apart when I got back home and found the problem to be a cable that came loose (the one running from the front panel dials to the regulator board) - so it was basically outputting the maximum voltage it could. Easy fix indeedIt has a fine/coarse adjustment, but I actually like it better. I hate turning the knob for hours upon hours before reaching the voltage I need (as I have to do with my other PS). This one is much faster to set, and for what I'm using it for I don't really mind if its 10.0 or 10.1. BTW, the fine adjustment allows setting the voltage quite precisely in under 10mV resolution - more than good enough for what I'm using it for. However, the voltage reading on the front panel only has a 100mV resolution so I'd have to use my DMM to set it more accurately. As far as the error of the measurement goes, the display is pretty accurate and agrees with my Agilent to within 40mV or so.There are a few problems with the PS as far as I can see, that make it a very bad design for most stuff:1 - The current limiting isn't limiting the current to the maximum set value, instead it turns the supply off when the current is higher than the set value. So forget about using it as a CCS.2 - Occasionally when first powered on the output jumps to over 5V for a very short duration before going back down and rising steadily as you'd expect it to. This really makes it a piece of crap when working on low voltage stuff, unless you add a regulator in between. Because of this I actually don't use it for anything below 5V (where I use my second PS), unless it has a regulator on-board. The third image I've attached shows how it jumps to about 7V.I did measure it under about 4A of load (I don't have anything that can survive more than that), and it performed well. I'm not sure how well it'll survive under full load for a long duration of time as the HS isn't as large as I'd think it should be - it is however, mounted outside of the case on the back panel so that should help a bit with cooling. To measure that I'll need a load that can survive 5A at 15V/very low voltages around 0V which I don't have. The PS has a switchable secondary, and 15V is the switching point, so these conditions will maximize the heat dissipation in the PS.The 4th image attached shows the output (AC coupled) when the output is set to maximum voltage (just over 30V) into ~8R resistor (measured current of 3.91A). This comes to about 0.03% ripple which is very nice considering the fact its a "SunRise" PS :LOL:So overall I'd say its a low quality PS, and it has issues (some of which can be easily fixed if I'd like to, but I simply don't want to spend any time/money on modifying this PS). However, I must say I'm quite happy with it. It has 2 channels of 30V-5A, it was very cheap, and the output ripple isn't too high. I'm using it for working on stepper motor drivers and it fits my needs completely.

author: T4P
author_rank: Super Contributor
timestamp: September 26, 2012, 10:36:45 am
content: The voltage output and the current limiting is a real joke, maybe it's better to harvest it for the chunky toroid thereFoldback current limiting is essentially useless

author: toli
author_rank: Frequent Contributor
timestamp: September 26, 2012, 10:48:48 am
content: That thought came to mind initially, but I've decided I can live with that. Who knows, maybe I'll find another PS for a good price and simply replace this one/save it for when I need more than 4 channelsThis one was just 23$, and my other PS was even less that that