best bang for buck 0-30V 0-40A power supply - Page 1
Forum section: electronics / testgear

author: Simon
author_rank: Unknown
timestamp: September 30, 2014, 11:14:15 am
content: power supply at work has just gone up in flames (mostly literally) they want me to find another one but I know it won't be cheap. Any ideas ?Main requirement is that it have a variable voltage output from around 3V and go up to 30V. current wise 40A minimum. seems that as soon as you pass the 30A mark at 30V they become and expensive and scarce.

author: grumpydoc
author_rank: Super Contributor
timestamp: September 30, 2014, 11:23:53 am
content: Digimess do bench PSUs that go up to 40A - £489 for 0-30V 0-40A switchmode.http://www.digimessinstruments.co.uk/powersupplies/No idea what the quality is - I've fixed up and resold a few of the 0-30V 0-20A linear PSUs and these are just the standard "Mastech" design - reasonably solid but nothing to wriite home about.

author: nctnico
author_rank: Super Contributor
timestamp: September 30, 2014, 11:25:21 am
content: If second hand is allowed: an HP6012A

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: September 30, 2014, 11:36:15 am
content: Best bang for buck is certainly going to be something used.Farnell did some nice ones - e.g.http://www.ebay.co.uk/itm/FARNELL-AP60-50-60VOLTS-50AMPS-POWER-SUPPLY-/381010203514?pt=UK_BOI_Electrical_Test_Measurement_Equipment_ET&hash=item58b5fa537ahttp://www.ebay.co.uk/itm/FARNELL-AP60-50-Regulated-Power-Supply-60V-50A-/251621321153?pt=LH_DefaultDomain_0&hash=item3a95cca9c1

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: September 30, 2014, 11:43:58 am
content: PS something to check about the Farnell ones, some have a power limit, so won't deliver the max current and voltage at the same time -= the ones I linked above have an indicator to show what's available at a particular setting.

author: Simon
author_rank: Unknown
timestamp: September 30, 2014, 11:44:51 am
content: Quote from: mikeselectricstuff on September 30, 2014, 11:36:15 amThe one that just blew is same range 3-30V 0-40A@30V lower than 30V the amps go up to 80A @ 12V, won't be able to afford one of those again.

author: Simon
author_rank: Unknown
timestamp: September 30, 2014, 11:45:42 am
content: Quote from: mikeselectricstuff on September 30, 2014, 11:43:58 amyep ours is marked as 30V 80A but it's 40A @ 30V and 80A @ 12V with a sliding scale for inbetween combinations.

author: eurofox
author_rank: Unknown
timestamp: September 30, 2014, 11:46:28 am
content: Quote from: Simon on September 30, 2014, 11:14:15 amIf you are happy with 30V 30A Manson provide one for less than 300 Euros, I have one

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: September 30, 2014, 11:48:30 am
content: Quote from: grumpydoc on September 30, 2014, 11:23:53 amI'd sooner buy a good used HP/Farnell etc. than a new cheapo Chinese unit.

author: Simon
author_rank: Unknown
timestamp: September 30, 2014, 11:51:47 am
content: We already have 1-30V 30A so that's no good and can get another any day. The killer is finding one to do 40A which we need to use at full capacity.

author: grumpydoc
author_rank: Super Contributor
timestamp: September 30, 2014, 11:56:29 am
content: QuoteAgreed but if he needs one in a hurry might have to compromise somewhere.

author: Simon
author_rank: Unknown
timestamp: September 30, 2014, 01:05:36 pm
content: http://uk.farnell.com/aim-tti-instruments/qpx1200s/power-supply-1ch-60v-50a-adjustable/dp/1908142I'm drooling, just looking to see if MCS can come up with one or similar.

author: nctnico
author_rank: Super Contributor
timestamp: September 30, 2014, 01:48:56 pm
content: Quote from: Simon on September 30, 2014, 11:51:47 amThe HP6012A can do that. It is rated for 1000W but at 30V it can deliver 40A (=1200W). The same goes for the newer HP6032A.

author: WVL_KsZeN
author_rank: Regular Contributor
timestamp: September 30, 2014, 02:12:58 pm
content: Delta elektronika make awesome power supplies.Http://www.delta-elektronika.nl. Check out the sm-1500 series that can do 1500w, 35v at 45a. They also make 3000 and 6000w supplies. Warning : they're not cheap at all, but will last your lifetime.http://www.delta-elektronika.nl/en/products/sm1500-series.html

author: artag
author_rank: Super Contributor
timestamp: September 30, 2014, 04:46:31 pm
content: The old farnell ones can be ganged in parallel. Probably most others can be too, as long as they have soft current limiting (no foldback).You might be able to get one identical to your 30V 30A and just put them in parallel.

author: Simon
author_rank: Unknown
timestamp: September 30, 2014, 04:51:43 pm
content: except ours is buggered (officially anyway) we need one supply.

author: SArepairman
author_rank: Frequent Contributor
timestamp: September 30, 2014, 05:23:55 pm
content: what are your requirements for electrical noise and size? Current limiting? type of read out? price limit?

author: Simon
author_rank: Unknown
timestamp: September 30, 2014, 05:25:36 pm
content: electrical noise not a problem as it's only automotive stuff. current limiting would be nice. We usually use the voltage and current readouts.

author: SArepairman
author_rank: Frequent Contributor
timestamp: September 30, 2014, 05:26:48 pm
content: Quote from: Simon on September 30, 2014, 05:25:36 pmmax price?

author: SArepairman
author_rank: Frequent Contributor
timestamp: September 30, 2014, 05:27:45 pm
content: how is this bad boy?http://www.ebay.com/itm/EMI-Lambda-TCR-0-40V-0-70A-2-8K-Watts-Variable-DC-Power-Supply-40S70-/261290946004?pt=LH_DefaultDomain_0&hash=item3cd6276dd4I will say that lamdba products are built like nuclear reinforced brick shit houses. My LQD420 lab supply is built mad nice, it has like the best construction out of any of my lab instruments. 3x as many screws as something twice its size lol

author: SArepairman
author_rank: Frequent Contributor
timestamp: September 30, 2014, 05:36:55 pm
content: this thing is bad ass toohttp://www.ebay.com/itm/EMI-TDK-Lambda-DC-Power-Supply-EMS-60-40-2-D-0-60V-0-40A-/321402674098?pt=LH_DefaultDomain_0&hash=item4ad5179bb2

author: Rufus
author_rank: Super Contributor
timestamp: September 30, 2014, 05:51:00 pm
content: Quote from: Simon on September 30, 2014, 01:05:36 pmI have a QPX1200L and yes it is very nice - looks like this inside....

author: nctnico
author_rank: Super Contributor
timestamp: September 30, 2014, 06:50:31 pm
content: That fan in the middle doesn't give me confidence the designer knew what he was doing.

author: KJDS
author_rank: Super Contributor
timestamp: September 30, 2014, 07:18:17 pm
content: Quote from: mikeselectricstuff on September 30, 2014, 11:36:15 amI've got a few of those in my "to be fixed sometime" pile. I really should get round to repairing more gear.

author: rolycat
author_rank: Super Contributor
timestamp: September 30, 2014, 07:58:52 pm
content: Quote from: Simon on September 30, 2014, 01:05:36 pmThat model doesn't quite match your stated requirements - it can only manage 26V at 40A.

author: nctnico
author_rank: Super Contributor
timestamp: September 30, 2014, 08:09:09 pm
content: Quote from: KJDS on September 30, 2014, 07:18:17 pmOr 'sell for parts'The value of equipent doesn't increase with age.

author: Simon
author_rank: Unknown
timestamp: October 01, 2014, 07:00:03 am
content: Quote from: rolycat on September 30, 2014, 07:58:52 pmhm true, it's a toss up between paying more for something flexible but still not perfect or paying less but getting something with a fixed top current, we need 28V so will have to guy 30V, at 1.2KW that is 40A, if we them drop to 20V tha means we now only have 800W of power. A 1.5KW would be ideal.

author: alex.forencich
author_rank: Frequent Contributor
timestamp: October 02, 2014, 01:04:20 am
content: How about this one?http://www.ebay.com/itm/Sorensen-SFA-60-83-Elgar-60-Volts-83-Amps-5-kW-DC-Power-Supply-SFA60-83C-0AAAAE-/191354235216?pt=LH_DefaultDomain_0&hash=item2c8d99e950Maybe 5 kW is a bit too much, though.

author: alex.forencich
author_rank: Frequent Contributor
timestamp: October 02, 2014, 01:14:15 am
content: This guy seems to have several of these available:http://www.ebay.co.uk/itm/Agilent-HP-6674A-60V-35A-2kW-System-Power-Supply-with-GPIB-3-/281435851572?pt=UK_BOI_Electrical_Test_Measurement_Equipment_ET&hash=item4186e24b34Not sure if you really want the bestbangfor your buck though. That sounds like it might get you back to where you are now.

author: Simon
author_rank: Unknown
timestamp: October 02, 2014, 05:41:39 am
content: We have ended up going with 30V 40A cheaper supply but getting 2 so we can parallel them. came out £3 more than the 1.2KW super duper one

author: Rufus
author_rank: Super Contributor
timestamp: October 02, 2014, 05:44:13 pm
content: Quote from: nctnico on September 30, 2014, 06:50:31 pmI expect they could have arranged for for more powerful fans at the back and perhaps some ducting to blow a crap load of air through the whole unit to make sure the main switching transformer got enough.They chose to use an internal fan to blow some air on the bit that gets hot, like just about every PC in the world does.

author: nctnico
author_rank: Super Contributor
timestamp: October 02, 2014, 06:38:21 pm
content: Quote from: Rufus on October 02, 2014, 05:44:13 pmYup. And just like in the PC that solution is crap. Creating more turbulence inside a case is not going to help cooling. Look at proper equipment from HP. The airflow is carefully ducted to flow along the parts which need it the most.

author: Simon
author_rank: Unknown
timestamp: October 02, 2014, 06:42:45 pm
content: modern PC's have just the one fan in the power supply usually, if you buy a replacement heatsink and fan they chuck the air stright at the power supply intake fan so minimal turbolence but still cooling the hotest part - the cpu

author: Towger
author_rank: Super Contributor
timestamp: October 02, 2014, 07:37:37 pm
content: If is it's must be cheap and you don't need CC or change the voltage, there are threads on RCGroups on using Server PSUs wired in series and using the sense lines to increased the voltage. You can pick them up on ebay for a few quid and they are by far the cheapest way of building a quality 1kw+ PSU.

author: Simon
author_rank: Unknown
timestamp: October 02, 2014, 08:01:17 pm
content: We needed variable voltage and CC allows bench supplies to be paralleled. We now have two 0-30V 0-40A supplies, we use 20-28V so 800-1120W of usable power each and 1600-2240W when paralleled, I will have to put a diode on each to prevent one feeding into the other if used in parallel.

author: nctnico
author_rank: Super Contributor
timestamp: October 02, 2014, 08:26:40 pm
content: Don't use a diode. At 40A that diode is likely to dissipate 40W or worse.

author: Simon
author_rank: Unknown
timestamp: October 02, 2014, 08:53:42 pm
content: so how do I stop one feeding into the other ? We can loose 40W price we pay for 2.2 KW @ £900 instead of £3Kwe don't need more than 28V so loossing 1V drop is no deal and we would be unlikely to use the full 40A from both.

author: Rufus
author_rank: Super Contributor
timestamp: October 02, 2014, 08:59:42 pm
content: Quote from: nctnico on October 02, 2014, 06:38:21 pmI'm sure the similarly specified 6032A has much nicer air flow - didn't think it was worth paying an extra £3500 for it.

author: romantao
author_rank: Contributor
timestamp: October 04, 2014, 01:14:09 pm
content: Recently just got a Xantrex XFR60-46 with GPIB option of ebay for 450euro.It's a rack model but it completely feeds my power needs!2760 W and maximum 46A at any voltage configuration it's a beauty!They don't come so often but spend some time looking or it!

author: nctnico
author_rank: Super Contributor
timestamp: October 04, 2014, 11:55:51 pm
content: Quote from: Simon on October 02, 2014, 08:53:42 pmIt is simple. As soon as one power supply hits it's current limit it wil drop the output voltage so the other power supply will deliver the rest of the current.

author: Smokey
author_rank: Super Contributor
timestamp: October 05, 2014, 01:35:04 am
content: Quote from: SArepairman on September 30, 2014, 05:27:45 pmI love lambda supplies, but the specs that ebay guy quotes seem to have a few two many zeros on the load regulation and current.

author: Simon
author_rank: Unknown
timestamp: October 05, 2014, 08:21:14 am
content: Quote from: nctnico on October 04, 2014, 11:55:51 pmYes but say the two supplies don't have the same voltage set (bearing in mind you can't "preset" these they switch on and deliver power with no enable button to allow you to set voltage and then start supplying) what will happen ?

author: oldway
author_rank: Super Contributor
timestamp: October 05, 2014, 12:21:38 pm
content: At home, I have a power supply who should match your requirements:SORENSEN DCS50-40M16 modified for local control with precision ten turns potentiometers to ajust voltage from 0 to 50V and current limit from 0 to 40A.http://theelectrostore.com/shopsite_sc/store/html/dcs50-40-power-supply-sorensen-DCS50-40M16.html

author: Simon
author_rank: Unknown
timestamp: October 05, 2014, 12:45:50 pm
content: Well we have now bought two power supplies so we not have 1600W - 2400W in the 20V-30v range if we put them in parallel, i think my boss wanted 1500W and that would be at around 24V

author: eurofox
author_rank: Unknown
timestamp: October 05, 2014, 12:58:03 pm
content: Quote from: oldway on October 05, 2014, 12:21:38 pmWhen you have problems with your Sorensen you will never find any service manual of diagram helping you to fix it.

author: oldway
author_rank: Super Contributor
timestamp: October 05, 2014, 01:17:07 pm
content: Never say NEVERhttp://exodus.poly.edu/~kurt/manuals/manuals/Other/SORENSEN%20DCS%20Series%20Instruction.pdfDiagram page 76

author: eurofox
author_rank: Unknown
timestamp: October 05, 2014, 01:24:39 pm
content: Quote from: oldway on October 05, 2014, 01:17:07 pmMaybe you just upload it now

author: oldway
author_rank: Super Contributor
timestamp: October 05, 2014, 01:48:26 pm
content: As I would have done also with all the SORENSEN manuals of the site !http://exodus.poly.edu/~kurt/manuals/manuals/Other/I modify and repair such power supplies, that's the reason why I have this documents on my computer since 2009.You should learn to use better Google before doing statements such as "you will NEVER find any service manual of diagram"

author: eurofox
author_rank: Unknown
timestamp: October 05, 2014, 02:01:39 pm
content: Quote from: oldway on October 05, 2014, 01:48:26 pmI'm very good at searching with google and I remember last year I was unable to find ANY manual or schematic about Sorensen, maybe this was not indexed by google.Site can be there but if they are off line sometimes and I just wonder if this was not the case with the Kurt site.I know this site and download sometimes manuals from there but check here before telling me that I cannot use google:https://www.eevblog.com/forum/testgear/noob-with-lecroy-9400a-dso/msg293158/#msg293158after finally downloading and reading the service manual, (the "kurt" site seems to be down most of the time.)I manage to finish removing the motherboard:

author: oldway
author_rank: Super Contributor
timestamp: October 05, 2014, 02:34:17 pm
content: QuoteI found it with Google in 2009 and I have download it on 16 july 2009.If you don't find a diagram, ask for it here, we will help you to find it !