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Cheap bench supply?

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ceengland7(at)gmail.com
Guest

Posted: Mon Dec 10, 2018 12:30 pm Post subject: Cheap bench supply?

On Tue, Nov 13, 2018 at 4:59 PM Charlie England <ceengland7(at)gmail.com (ceengland7(at)gmail.com)> wrote:



 	  Quote: 	
		  Anyone have experience with the recent ebay offerings for cheap lab supplies? Example below. I tried searching my old AEC emails, but the most recent reference I found was for a much more expensive model. It'll get minimal use; just final checkout of my project's wiring and then rare uses after that, so don't want to spend $hundreds. 

0-30v/0-10a bench supply



Thanks,

Charlie



	




Well, I said I'd publish a pirep once I received the unit, so here we go.

The unit seems to work just fine, with a couple of 'idiosyncrasies'.  The controls are analog, as you'd expect from the pairs of coarse  & fine adjustment knobs. The only frustrating thing is that current limit is set by setting voltage to some reasonably low value, setting current to minimum, shorting out the + & - terminals, and then dialing up the current knobs to the desired limit. Then remove the short and connect your load. At loads less than the current set point, the voltage display shows your set point voltage (actual output voltage). The current display will vary between zero and the current set point, depending on actual load. Once the current limit is reached, voltage (and the displayed voltage, of course) falls to limit current to the preset level. 

Behavior of the supply is as expected, but it is frustrating to not see the actual current limit set point while in operation, until you actually hit the limit. Since the knobs are unmarked, this requires going back through the limit setting for each new work session, unless you trust that the current limit knobs haven't been touched since the last session. The ideal supply would have both set point and output displays, but for my limited needs, I don't need to pay for ideal. 

Assuming long term survival, I consider it a great value compared to the $hundreds required for lab grade supplies.

Charlie



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ashleysc(at)broadstripe.n
Guest

Posted: Mon Dec 10, 2018 7:45 pm Post subject: Cheap bench supply?

Hi Charlie;

Bought one. Haven't used it yet. Check back.

Cheers!   Stu.

From: "Charlie England" <ceengland7(at)gmail.com>

To: aeroelectric-list(at)matronics.com

Sent: Monday, December 10, 2018 12:29:39 PM

Subject: Re: Cheap bench supply?

On Tue, Nov 13, 2018 at 4:59 PM Charlie England <ceengland7(at)gmail.com (ceengland7(at)gmail.com)> wrote:

 	  Quote: 	
		  Anyone have experience with the recent ebay offerings for cheap lab supplies? Example below. I tried searching my old AEC emails, but the most recent reference I found was for a much more expensive model. It'll get minimal use; just final checkout of my project's wiring and then rare uses after that, so don't want to spend $hundreds. 

0-30v/0-10a bench supply

Thanks,

Charlie

Well, I said I'd publish a pirep once I received the unit, so here we go.

The unit seems to work just fine, with a couple of 'idiosyncrasies'.  The controls are analog, as you'd expect from the pairs of coarse  & fine adjustment knobs. The only frustrating thing is that current limit is set by setting voltage to some reasonably low value, setting current to minimum, shorting out the + & - terminals, and then dialing up the current knobs to the desired limit. Then remove the short and connect your load. At loads less than the current set point, the voltage display shows your set point voltage (actual output voltage). The current display will vary between zero and the current set point, depending on actual load. Once the current limit is reached, voltage (and the displayed voltage, of course) falls to limit current to the preset level. 

Behavior of the supply is as expected, but it is frustrating to not see the actual current limit set point while in operation, until you actually hit the limit. Since the knobs are unmarked, this requires going back through the limit setting for each new work session, unless you trust that the current limit knobs haven't been touched since the last session. The ideal supply would have both set point and output displays, but for my limited needs, I don't need to pay for ideal. 

Assuming long term survival, I consider it a great value compared to the $hundreds required for lab grade supplies.

Charlie

  	          		Virus-free. www.avast.com 		 	 [url=#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2][/url]

nuckolls.bob(at)aeroelect
Guest

Posted: Mon Dec 10, 2018 8:44 pm Post subject: Cheap bench supply?

 	  Quote: 	
		  

 Behavior of the supply is as expected, but it is frustrating to not see the actual current limit set point while in operation, until you actually hit the limit. Since the knobs are unmarked, this requires going back through the limit setting for each new work session, unless you trust that the current limit knobs haven't been touched since the last session. The ideal supply would have both set point and output displays, but for my limited needs, I don't need to pay for ideal. 



 Assuming long term survival, I consider it a great value compared to the $hundreds required for lab grade supplies. 	




   Your observations are typical of every knob-adjusted power

   supply I've worked with for decades. The only devices

   with pre-set current/voltage values are digitally

   addressed. I have one of these guys in my stable:



  https://tinyurl.com/ydxv9edb



   It performs as advertised but in my opinion,

   not nearly as 'agile' as the 4-knob, analog

   supplies. But I do confess to being functionally

   predisposed. Been using those critters since

   '63.



   



 

 

   Bob . . .

cluros(at)gmail.com
Guest

Posted: Mon Dec 10, 2018 10:13 pm Post subject: Cheap bench supply?

For those of us who do not care about limiting the current, is there a cheaper way of getting 20A between 5 and 30V?



On Mon, Dec 10, 2018, 20:49 Robert L. Nuckolls, III <nuckolls.bob(at)aeroelectric.com (nuckolls.bob(at)aeroelectric.com) wrote:



 	  Quote: 	
		     	  Quote: 	
		  

 Behavior of the supply is as expected, but it is frustrating to not see the actual current limit set point while in operation, until you actually hit the limit. Since the knobs are unmarked, this requires going back through the limit setting for each new work session, unless you trust that the current limit knobs haven't been touched since the last session. The ideal supply would have both set point and output displays, but for my limited needs, I don't need to pay for ideal. 



 Assuming long term survival, I consider it a great value compared to the $hundreds required for lab grade supplies. 	




   Your observations are typical of every knob-adjusted power

   supply I've worked with for decades. The only devices

   with pre-set current/voltage values are digitally

   addressed. I have one of these guys in my stable:



  https://tinyurl.com/ydxv9edb



   It performs as advertised but in my opinion,

   not nearly as 'agile' as the 4-knob, analog

   supplies. But I do confess to being functionally

   predisposed. Been using those critters since

   '63.



   



 

 

   Bob . . .

yellowduckduo(at)gmail.co
Guest

Posted: Tue Dec 11, 2018 4:13 am Post subject: Cheap bench supply?

One can usually replace the analog current potentiometer with a multi 

position rotary switch and fixed resistors if preferred. I find that 

about 6 positions suits my bench supply just fine.

Ken



On 10/12/2018 3:29 PM, Charlie England wrote:

 	  Quote: 	
		  



 On Tue, Nov 13, 2018 at 4:59 PM Charlie England <ceengland7(at)gmail.com 

 <mailto:ceengland7(at)gmail.com>> wrote:



     Anyone have experience with the recent ebay offerings for cheap

     lab supplies? Example below. I tried searching my old AEC emails,

     but the most recent reference I found was for a much more

     expensive model. It'll get minimal use; just final checkout of my

     project's wiring and then rare uses after that, so don't want to

     spend $hundreds.

     0-30v/0-10a bench supply

     <https://www.ebay.com/itm/10A-Digital-DC-Power-Supply-Variable-Adjustable-Lab-Bench-Test-Equipment-Tool/202435783331?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m1438.l2649>



     Thanks,



     Charlie

 Well, I said I'd publish a pirep once I received the unit, so here we go.



 The unit seems to work just fine, with a couple of 'idiosyncrasies'. 

 The controls are analog, as you'd expect from the pairs of coarse  & 

 fine adjustment knobs. The only frustrating thing is that current 

 limit is set by setting voltage to some reasonably low value, setting 

 current to minimum, shorting out the + & - terminals, and then dialing 

 up the current knobs to the desired limit. Then remove the short and 

 connect your load. At loads less than the current set point, the 

 voltage display shows your set point voltage (actual output voltage). 

 The current display will vary between zero and the current set point, 

 depending on actual load. Once the current limit is reached, voltage 

 (and the displayed voltage, of course) falls to limit current to the 

 preset level.



 Behavior of the supply is as expected, but it is frustrating to not 

 see the actual current limit set point while in operation, until you 

 actually hit the limit. Since the knobs are unmarked, this requires 

 going back through the limit setting for each new work session, unless 

 you trust that the current limit knobs haven't been touched since the 

 last session. The ideal supply would have both set point and output 

 displays, but for my limited needs, I don't need to pay for ideal. 



 Assuming long term survival, I consider it a great value compared to 

 the $hundreds required for lab grade supplies.



 Charlie



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 	Virus-free. www.avast.com 

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rickofudall

Joined: 19 Sep 2009
Posts: 1392
Location: Udall, KS, USA

Posted: Tue Dec 11, 2018 7:49 am Post subject: Cheap bench supply?

Get some number transfers so you can set the knobs to the same settings you require. Set the top to 11 and watch "Spinal Tap" for a giggle. :-}



Rick

On Tue, Dec 11, 2018 at 6:18 AM C&K <yellowduckduo(at)gmail.com (yellowduckduo(at)gmail.com)> wrote:



 	  Quote: 	
		  --> AeroElectric-List message posted by: C&K <yellowduckduo(at)gmail.com (yellowduckduo(at)gmail.com)>

 

 One can usually replace the analog current potentiometer with a multi 

 position rotary switch and fixed resistors if preferred. I find that 

 about 6 positions suits my bench supply just fine.

 Ken

 

 On 10/12/2018 3:29 PM, Charlie England wrote:

 >

 >

 > On Tue, Nov 13, 2018 at 4:59 PM Charlie England <ceengland7(at)gmail.com (ceengland7(at)gmail.com) 

 > <mailto:ceengland7(at)gmail.com (ceengland7(at)gmail.com)>> wrote:

 >

 >     Anyone have experience with the recent ebay offerings for cheap

 >     lab supplies? Example below. I tried searching my old AEC emails,

 >     but the most recent reference I found was for a much more

 >     expensive model. It'll get minimal use; just final checkout of my

 >     project's wiring and then rare uses after that, so don't want to

 >     spend $hundreds.

 >     0-30v/0-10a bench supply

 >     <https://www.ebay.com/itm/10A-Digital-DC-Power-Supply-Variable-Adjustable-Lab-Bench-Test-Equipment-Tool/202435783331?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m1438.l2649>

 >

 >     Thanks,

 >

 >     Charlie

 >

 >

 > Well, I said I'd publish a pirep once I received the unit, so here we go.

 >

 > The unit seems to work just fine, with a couple of 'idiosyncrasies'. 

 > The controls are analog, as you'd expect from the pairs of coarse  & 

 > fine adjustment knobs. The only frustrating thing is that current 

 > limit is set by setting voltage to some reasonably low value, setting 

 > current to minimum, shorting out the + & - terminals, and then dialing 

 > up the current knobs to the desired limit. Then remove the short and 

 > connect your load. At loads less than the current set point, the 

 > voltage display shows your set point voltage (actual output voltage). 

 > The current display will vary between zero and the current set point, 

 > depending on actual load. Once the current limit is reached, voltage 

 > (and the displayed voltage, of course) falls to limit current to the 

 > preset level.

 >

 > Behavior of the supply is as expected, but it is frustrating to not 

 > see the actual current limit set point while in operation, until you 

 > actually hit the limit. Since the knobs are unmarked, this requires 

 > going back through the limit setting for each new work session, unless 

 > you trust that the current limit knobs haven't been touched since the 

 > last session. The ideal supply would have both set point and output 

 > displays, but for my limited needs, I don't need to pay for ideal. 

 >

 > Assuming long term survival, I consider it a great value compared to 

 > the $hundreds required for lab grade supplies.

 >

 > Charlie

 >

 > <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail&utm_term=icon> 

 >       Virus-free. www.avast.com 

 > <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail&utm_term=link> 

 >

 >

 

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nuckolls.bob(at)aeroelect
Guest

Posted: Thu Dec 13, 2018 9:05 am Post subject: Cheap bench supply?

At 12:12 AM 12/11/2018, you wrote:

  	  Quote: 	
		  For those of us who do not care about limiting the current, is there a cheaper way of getting 20A between 5 and 30V? 	


   That's going to be a 600W supply . . . pretty rare

   in the constellation of off-shore offerings to hobbyists.



   Fixed voltage supplies in that power class are readily

   available, here's one example



  https://tinyurl.com/y6tw6k6o



   Adjustable supplies with that capability

   are more likely to be found as used,

   lab grade power supplies like this

   excellent buy



  https://tinyurl.com/ybgkh4ov



   . . . but trust me, supplies in this

   power class are capable of much smoke.

   You will come to LOVE that current

   limiting feature.



 



 

 

   Bob . . .

user9253

Joined: 28 Mar 2008
Posts: 1921
Location: Riley TWP Michigan

Posted: Thu Dec 13, 2018 10:42 am Post subject: Re: Cheap bench supply?

That excellent buy costs $92 to ship. It must be big and heavy.

_________________
Joe Gores

nuckolls.bob(at)aeroelect
Guest

Posted: Thu Dec 13, 2018 11:52 am Post subject: Cheap bench supply?

At 12:42 PM 12/13/2018, you wrote:

  	  Quote: 	
		  --> AeroElectric-List message posted by: "user9253" <fransew(at)gmail.com>



 That excellent buy costs $92 to ship.  It must be big and heavy. 	


  Yup . . . probably 40 pounds. They're rack mounted

  supplies about 9 inches high.  I have one on my

  bench. Had it about 15 years and it was

  10-15 years old when I got it. It's HP . . . built

  to last. Probably cost about $3000 new.



 

 

   Bob . . .

nuckolls.bob(at)aeroelect
Guest

Posted: Thu Dec 13, 2018 11:58 am Post subject: Cheap bench supply?

At 12:42 PM 12/13/2018, you wrote:

  	  Quote: 	
		  --> AeroElectric-List message posted by: "user9253" <fransew(at)gmail.com>



 That excellent buy costs $92 to ship.  It must be big and heavy. 	


  Yup . . . probably 40 pounds. They're rack mounted

  supplies about 9 inches high.  I have one on my

  bench. Had it about 15 years and it was

  10-15 years old when I got it. It's HP . . . built

  to last. Probably cost about $3000 new.



  CORRECTION. Closer to 40 years old when I

  got it and they're 93 pounds.



 

 

   Bob . . .

lyn.robertson(at)gmail.co
Guest

Posted: Thu Dec 13, 2018 2:34 pm Post subject: Cheap bench supply?

The HP stands for “heavy product”. 

On Thu, Dec 13, 2018 at 12:03 Robert L. Nuckolls, III <nuckolls.bob(at)aeroelectric.com (nuckolls.bob(at)aeroelectric.com)> wrote:



 	  Quote: 	
		    At 12:42 PM 12/13/2018, you wrote:

  	  Quote: 	
		  --> AeroElectric-List message posted by: "user9253" <fransew(at)gmail.com (fransew(at)gmail.com)>



 That excellent buy costs $92 to ship.  It must be big and heavy. 	


  Yup . . . probably 40 pounds. They're rack mounted

  supplies about 9 inches high.  I have one on my

  bench. Had it about 15 years and it was

  10-15 years old when I got it. It's HP . . . built

  to last. Probably cost about $3000 new.



  CORRECTION. Closer to 40 years old when I

  got it and they're 93 pounds.



 

 

   Bob . . .

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