Wattmeter Lutron DW-6090 (Peaktech 2510 or PCE-PA 6000) teardown

[mcinque]

This is a "cheap" power analyzer with serial interface that reads (and logs via SW) Watts, CosPhi/Hertz, Ampere of a DUT on a big single screen.
It can read ACA and DCA (in this second mode the reading is only V and A) and it's powered by batteries or by a wall adapter.

The "curious" thing is that you can find this rebranded by different companies, but at really different prices.

The "original" from Lutron (Taiwan) has a price a little bit high, € 566,00 + shipping without interface cable, software and wall adapter (Distrelec). If you want software and interface cable you must add € 158,00 for a grand total of € 883,00.
The Peaktech (Germany) costs € 379,00 + shipping, and has interface cable and software, but no wall adapter.
The PCE (Germany) costs € 328,00 + shipping, also with serial interface and software but no wall adapter.
I found also other rebranded versions.

Since I researched a lot before purchasing this instrument but I didn't find any teardown pictures, I'd like to share them for other people searching for them.

The internal construction isn't rocket science, basically it's a big shunt resistor and a volt/ammeter with CosPhi calculation.
The readings are a little bit out from spec in some readings.
The upper PCB was very dirty of flux, I cleaned it because it looked awful.

The general construction isn't Agilent quality of course, but neither disgusting.
The serial interface is of course optically isolated from the remaining circuit, and also the power switch and power supply circuitry. You can see a gas discharger between inputs and a 9M resistor between the black sense wire and the external input, plus other isolation slots where mains goes on the PCB.

Some quick readings I got on pure resistive loads (the readings on the DM3058 are calculated doing V*I)

LOAD (light bulbs)  DM3058   DW-6090   DIFF   ERR 1-1,5%
48W   CosPhi 1      49,5W      48,7W       0,8W   IN SPEC (should be 0,74W for spec but my mains V is a little bit unstable so this probably is an error on V and I reading)
30W   CosPhi 1      32,2W      31,9W       0,3W   IN SPEC
15W   CosPhi 1      11,8W      11,9W       0,1W   IN SPEC

The input impedance is 1M on AAC and ADC, but in R position is only 150K, I suspect that having mains on the input and selecting R can bring to catastrophic failure: the input protection is max 300V in this position but I wonder how much time it can handle mains.

[OZ1LQO]

I bought this unit used (branded Peaktech) and besides a battery compartment with leaked Duracells (seriously, even the 'industry grade  ') it was ok.

I checked its performance with a range of non-purely-resistive loads (LED lamps, transformers, etc) and it was dead on comparing with a calibrated Voltech PM-300 I have access to at work.

Looking inside I didn't find a dedicated energy meter chipset as can be found in the various meters you can buy at Amazon, eBay, AliExpress, etc. (they're surprisingly accurate btw).

It's a nice instrument with a good build quality and a very decent performance indeed. They're reasonably priced and if you can find a used one, it's almost a no-brainer addition to the lab 

cheers