Category Archives: Hardware Hacking

Electronics Hardware Hacking

Doubts about the IGBT isolated drive voltage

Fresh out of repair I hooked up my IGBT pack for testing one channel. I had vaporized some traces off the secondary supply voltage. I hooked up the load, the low voltage drive and then my best guess on the isolated power supply. I guessed wrong. I was hoping because the Chiller had a good 4 or 5 24VAC secondary transformers and 24VAC is ubiquitous throughout the HVAC world. I guessed wrong. I let some more smoke out.

I am lucky I have a new friend who works on Chillers. He hooked me up with the water-cooled heat sink and I have a pump and some capacitors coming to me as well. I’m going to ask him to let me poke into an operating board with my multimeter next time we are working together to find out whats going on. The pair of wires is feeding 6 isolation transformers in parallel with what I thought were MOVs but it’s hard to tell, no markings and I doubt my soldering skills could get them safely off and back on again? Maybe…

Well back to the drawing board… rumor has it they might have another (smaller) drive out of a refurbished unit…. could I be so lucky?

IGBT pack married to it's heat sink
IGBT pack married to it’s heat sink
Electronics Hardware Hacking

Lithium Battery Boost Power Supply Comparison

I purchased two boost converters or DC to DC power supplies, or whatever else people want to call them on eBay. One was a LiPower board from Sparkfun for $14.95. I assume it’s made in the US, has a battery connector and can be soldered with 0.1in pitch terminals. It’s setup for low voltage drop out at 2.6V but there is a small hack to reduce that (though I feel like you have better options if you’re trying two NiMH batteries because it has reduced current abilities from the hack.) See the sparkfun site for more details, including the link to the hardware hack. The output is a small solder jumper that comes preset to 5V but wouldn’t take but a minute to convert to 3.3V.  https://www.sparkfun.com/products/10255

I put a small load (my anticipated load of a project) of 50mA and this device measured at 85.3% efficient.

The other device I bought was a cheap-o Chinese converter that came as a two-pack from Hong Kong. It came with a USB connector and took anything 2 to 5V. I tested this with a 2.4V battery pack and it seems to cut out at just under 2V. The efficiency was measured at 77.0%… Also with a 50mA load. My input voltage was a bench power supply set to 3.7V to simulate a LiPo battery on both tests. A nicety of the Chinese “mobile booster” board was the red LED showing output power status. The LED blinks rapidly when it goes into low voltage cutout. The cheap-o board also output 5.20v which was fine for my application. I think I gave roughly $4 both boards with free shipping.

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Electronics Hardware Hacking

IGBT Pack and Drive Pin Diagram

So if anyone runs into an IGBT pack from a York Chiller I’ll do you a solid and give you a pin diagram.

York part number: 031-02061-001

The connector is of this style (p/n from package, I forget which side): 1-794223-0 http://www.digikey.com P/N: A100435CT-ND .. using this you can find both pieces.

.. all TTL is 5V the “/” is a low level input designator. PIN

1: U1 (5VDC)

2: U1+U2 /FAULT

3: U4

4: U5

5: U5+U6 /FAULT

6. T1 (RTD 5K)

7. DC NEG

8. Vcc (5VDC)

9. Isolated Power (I think this is 24VAC but I’m not sure)

10. U2

11. U3

12. U3+U4 /FAULT

13. U6

14. /RESET

15. T2 (RTD)

16. N/C

17. DC NEG

18. Other side of isolated input I believe.. I blew mine up before I could fully test this.

… as for the IGBT it’s 2, 4, 6 are + (up to 1.2kV) and 1, 3, 5 are the negative side, the others are the 3 phase output. New, this pack is painfully expensive.. $1,400 but maybe you’ll run into a good deal or some “garbage” as I did. Good luck!