Mastech HY3003D-2 can switch to 110 from 220? - Page 1
Forum section: electronics / beginners

author: xkip
author_rank: Newbie
timestamp: August 24, 2018, 04:26:53 pm
content: Hello, I'm planing to move to Canada. So, reviewing my hardware if it can works or can be converted to 110v.In general user manual for this power supply (that fits to all models) there is a switch on the back that supposed to switch between 110V & 200V modes.But in my case this hole is actually covered by sticky label that states this is 220V only. While inside the device there is a paper label 110/220. It is true that there is no switch.I've seen couple schematics, but none of them includes this switch... Does any body have proper schematics for it?I feel like it depends from coil layout... If it have 2 separate primary coils and they are chained in serial to work in 220V I hope I can rework this a little bit to go parallel instead (this is probably what actually switch supposed to do). Am I somehow close to the solution or this device might have different coil voltage for different markets and conversion is not possible in my case?

author: tooki
author_rank: Super Contributor
timestamp: August 24, 2018, 08:45:56 pm
content: See the little front-panel switch circuit board? It's got two red wires coming in from the mains, and orange-green-orange-green going out to the transformer. As you said, for 230V (as configured) the two primary windings are in series; for 120V* you put them in parallel. (You'd need to test the exact color coding, since it's possible that one primary winding is orange and the other is green — or that each winding is orange on one end and green on the other.) Quite possibly, that's exactly what the unused connector footprint on the switch PCB does. (Either that, or the second connector is for the input voltage switch, and when that's not used, jumpers are installed. My HY3005 clone is like that.)*It's not 110V and hasn't been for nearly 100 years!

author: ArthurDent
author_rank: Super Contributor
timestamp: August 25, 2018, 11:52:01 am
content: I believe tooki is correct except in some parts of the world it is actually 110VAC, not 120VAC.I 'think' if you unplug the connector with the green/orange wires and check how the runs on the underside of the board connect the pins for the connectors that aren't there, you may find that one of the two blank connector locations is wired like the drawing I've included. If there was a connector in the correct one of the two blank positions you could just move the green/orange connector to the other position to change from series (220) to parallel (110) instead of having a switch on the back. This would connect the two green wires together to one side of the line and the two orange wires together to the other side of the line. You can probably check the board wiring from the topside with small probes on a DMM. The small difference between 110 and 120 shouldn't matter either plus you're probably going from a 50 hertz world to a 60 hertz world that will reduce the no load (excitation) current for the transformer as well. If you can find another 4-pin connector to solder in the correct position (or move the existing one) you will be able to make this voltage change without cutting and modifying any wiring which would keep it neater.One word of warning: if the two primary windings are placed in parallel out of phase, this will blow a fuse. If you put a 100 watt incandescent bulb in series with the transformer primary the first time you try it after making the change in the primary wiring and the bulb doesn't glow brightly, and the supply works, it is wired correctly.

author: tooki
author_rank: Super Contributor
timestamp: August 25, 2018, 01:10:20 pm
content: Quote from: ArthurDent on August 25, 2018, 11:52:01 amExcept the OP isn't moving to "some part" of the world, they expressly said "Canada", which is 120V.Good call on the phase, though!

author: ArthurDent
author_rank: Super Contributor
timestamp: August 25, 2018, 01:44:46 pm
content: "Except the OP isn't moving to "some part" of the world, they expressly said "Canada", which is 120V."You misunderstood what I meant. I live in this 120VAC/60 hertz world and understand that. Check the labels shown in the first post which read '110V/220V' and the frequency listed on the back of the supply read '50Hz'. The point was that there are 110VAC countries even today and the supply was labeled for those areas.

author: tooki
author_rank: Super Contributor
timestamp: August 25, 2018, 02:08:39 pm
content: Quote from: ArthurDent on August 25, 2018, 01:44:46 pmBut the back panel label says "207-253V", which is 230V±10%. Half that is 115V, which is the compromise between 110V and 120V.I chalk up the internal 110/220V to be either the manufacturer's shorthand for which voltage version it is, or simply carelessness.I have no idea why it bugs me so much that people routinely call USA/CA 110V instead of 120V (or Europe 220V instead of 230V), but it's a huge pet peeve of mine.I'd love to see an authoritative list of world voltages. Every list I've managed to find is a compilation of what someone scrounged around the Internet or from documents so old as to be irrelevant. (Just like most of the simple 2-prong adapters for US-to-Euro plugs conform neither to modern NEMA nor Europlug standards!)

author: Jwillis
author_rank: Super Contributor
timestamp: August 25, 2018, 11:29:27 pm
content: The 110V-127V is a North American standard .It's not specifically set to 120V because of line load variances.My AC can peak as high as 125V and as low as 110V depending on the time of day.All electrical products are designed to handle these variances.If the transformer has 3 or more primary taps then its designed for multiple input voltages.2 Orange and 2 green are the primaries.Here's a few pics of mine for Canada and a schematic of a HY3020 Aside from extra components and outputs theirs little difference between the 3005 ,3010 and 3020

author: tooki
author_rank: Super Contributor
timestamp: August 26, 2018, 12:02:14 am
content: Quote from: Jwillis on August 25, 2018, 11:29:27 pmYou are confusing nominal voltage and tolerances. In North America, the nominal voltage is, and has been for decades, 120V. Not 115, not 117, not 125, not 127, and not 110. It is 120V and the tolerance is ±10% (NEMA).https://www.pge.com/includes/docs/pdfs/mybusiness/customerservice/energystatus/powerquality/voltage_tolerance.pdfexplains this in great detail.

author: Jwillis
author_rank: Super Contributor
timestamp: August 26, 2018, 01:14:38 am
content: If you want to split hairs then fine whatever.The point is that it doesn't matter if product in question says 110v,115v,117v.120V or 125v it falls within range of the North American standard .The true line voltage will never be exactly 120V EVER.This is because grid loads change constantly through out the day.As long as it falls between 110V and 127V you have adequate supply.But this is not the point of the OP's question.His states 110V/220V where as mine states 115V/230V on virtually identical units and he wants to convert his from 220V to 110V .Yes it can be done by putting the primaries in parallel Green to Green Orange to Orange . It will fall within the except able range of North American household voltages.

author: ArthurDent
author_rank: Super Contributor
timestamp: August 26, 2018, 02:41:41 am
content: After looking at the photos in post #6 I'm convinced that my original assumption of how the pins were connected was wrong and that the photo of the underside of the board in post #6 is how the board in the original post is wired. Not being able to actually see the power supply and check the primaries for continuity puts us at a big disadvantage.The runs on the underside of the switch circuit board connect all inline group of 3 connector pads together and I have changed my drawing to reflect that. What we can't see in post #1 is that there 'probably' is a jumper between the two middle pins to put the two primary windings in series for 230VAC. The voltage selector switch isn't used and one jumper wire is much cheaper. I 'think' now that the two primary windings are green to green and orange to orange. The proper jumpers for 120VAC would be to jumper each outside connector pad to the one next to it as I have shown in the revised drawing.I'll include the same warning on testing if this is correct. if the two primary windings are placed in parallel out of phase, this will blow a fuse. If you put a 100 watt incandescent bulb in series with the transformer primary the first time you try it after making the change in the primary wiring and the bulb doesn't glow brightly, and the supply works, it is wired correctly.

author: Jwillis
author_rank: Super Contributor
timestamp: August 26, 2018, 03:30:31 am
content: Looks like an identical switch board.I can't see all J1.its possible theirs a jumper on the 2 center pins( pin2 and pin3) .Might be as easy as pulling that jumper and replacing with 2 jumpers that connect the green and the orange wires in parallel.If I'm correct jump pin 1 to pin 3 and pin 2 to pin 4 .That's really all the mains select does.I would have to see the under side of his switch board.I have other toriods and non of the primaries have miss matched colored wires .But this has got me thinking if I could "up grade" mine for more current.Any one have photos of a HY3010 or HY3020 ? Sorry the schematic is a HY3005 not a HY3020