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Eltek Flatpack2 PSU 3KW set to 48V or whatever you want.
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On 26/01/2021 15:45, Mike Willis wrote:
Eltek Flatpack2 PSU I have loads of 3KW set to 48V or
whatever you want. £72 each plus postage. This price only to
forum members.
73 Dave G4IUG Ex G8EAO
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Robin Szemeti - G1YFG
Do you happen to know the maximum voltage they will do?
On Tue, 26 Jan 2021 at 16:03, Dave Cawley G4IUG <help@...> wrote:
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Robin Szemeti - G1YFG
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They say 57.6 VDC. However, with surgery that might be tweaked further......
https://www.eltek.com/products/flatpack2-48v-she/ -- 73, Paul Evans G4BKI [VP9KF]
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Mike Willis
There is a bargain. Ideal for that LDMOS 400W (cough) PA.
-- Mike G0MJW
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Robin Szemeti - G1YFG
Might be just enough for my QRP 65V LDMOS 2m slab ;) I run one of the 1500W ones on my 23cm linear and it is exceptionally good, no sproggies, mains current draw is close to sinusoidal. I'll check the coffers, unfortunately, she spotted I had been spending money on large relays and 6cm PA's ... she was giving me the "I've been adding all this up" eye the other night ;)
On Tue, 26 Jan 2021 at 16:19, Mike Willis <willis.mj@...> wrote: There is a bargain. Ideal for that LDMOS 400W (cough) PA. --
Robin Szemeti - G1YFG
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On 26/01/2021 16:11, Robin Szemeti - G1YFG wrote:
Do you happen to know the maximum voltage they will do?It varies, about 58V. I set up each one on CAN-bus and load/soak test it. 73 Dave
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Mike Willis
Dave
Some questions. What's the minimum voltage? Are the 2k and 3k the same enclosure and connections? I have two of the 2K Flatpack2 HE so not sure I need another, but a 3K might be interesting. So far all I have taken from them is 10A testing my rather inefficient 2.4 GHz PA. What happens it you take that load and put a relay in series and turn it on and off fairly quickly? One would hope nothing untoward but I haven't tested that yet. I have a 1 ohm 100W resistor and a 1kW 50 ohm dummy load, but nothing that would test a supply like that. -- Mike G0MJW
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I've tested a PSU like that (well, only 20A max) using vastly underrated resistors in a bucket of water Think I used 2W ones dissipating >10W each.. they survived. Or you could get some enameled wire, calculate the length for your given test resistance (*), and again, stick in a bucket of water Done that as well (*) R = 1.7E-8 * Length / Area Area = pi . Diameter^2 / 4 All in SI units eg. 0.5mm wire. A = 0.196E-6 m^2 R = 0.086 ohms/m Andy
On Tue, 26 Jan 2021 at 17:52, Mike Willis <willis.mj@...> wrote: Dave
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On 26/01/2021 17:52, Mike Willis wrote:
What's the minimum voltage? Are the 2k and 3k the same enclosure and connections? I have two of the 2K Flatpack2 HE so not sure I need another, but a 3K might be interesting. So far all I have taken from them is 10A testing my rather inefficient 2.4 GHz PA. Hi Mike The 2K and 3K I have here are physically and electrically identical. The lowest voltage is about 44V Many people have used these with 1.5KW and more amplifiers, effectively drawing well over 2KW input and dynamically they are fine for SSB. 73 Dave The
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Robin Szemeti - G1YFG
Put me down for a 3kw, I'll sort out payment after the SHF UKAC, my 13cm PA seems to have blown the first driver stage so I am a weeeee bit down on power tonight ... I think about 5 or 6 W ..
On Tue, 26 Jan 2021 at 18:52, Dave Cawley G4IUG <help@...> wrote:
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Robin Szemeti - G1YFG
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alwyn.seeds1
Dear All,
I have not tested this model of power supply, but have found that a number of similar types produce switching frequency sidebands on the amplifier output under J3E drive. A quick check is to run a two tone test and look carefully out to +/- 200 kHz from the signal with a good receiver or spectrum analyser. Some power supplies are OK on two tone testing, but produce bursts of switching frequency sidebands under speech modulation- again, careful tuning around the signal will find this. On one commercial linear, I had to add a high current low pass filter to get this noise down to RSGB contest Code of Practice levels. Of course, these effects may be less of a problem on microwave bands than on busy bands, such as 2m, but forewarned is forearmed. Regards, Alwyn G8DOH _____________________________________________________ Alwyn Seeds, Director SynOptika Ltd., 114 Beaufort Street, London, SW3 6BU, England. SynOptika Ltd., Registered in England and Wales: No. 04606737 Registered Office: 114 Beaufort Street, London, SW3 6BU, United Kingdom. _____________________________________________________
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Robin Szemeti - G1YFG
I think at least part of the problem is they have somewhere between "none" and "very little" output capacitance. They were designed for battery charging in 48V systems, which is a slowly changing a predictable load. Mine had basically no bulk output capacitance, just typical 3 pole low pass filter. On the one I use on 23cm, a good amount of large capacitance on the output helped a lot, reducing the current peaks the PSU saw and giving it a chance to catch up and much improved the output noise. I suspect on 2m it will need a very careful assessment.
On Wed, 27 Jan 2021 at 08:35, alwyn.seeds1 <a.seeds@...> wrote:
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Robin Szemeti - G1YFG
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Mike Willis
Put me down for one then and I will test it out. I have been really happy with the 2kw model and I have a space interface board on hand.
-- Mike G0MJW
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I believe I have replied to everyone
who asked, if not let me know. The price is £72.00 set to your
voltage and load/soak tested, plus £10.00 for second class
signed for post. England, Scotland, Wales and Northern Ireland
only.
73 Dave G4IUG Ex G8EAO
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Does anyone here know the CAN bus? I read the spec a good few years ago and know the basics but have never used it, or ever had to. Seems to have an interesting priority approach based on wired-OR to collision detection. Wondering if a PIC based gizmo could be used to send adjustable voltage setting commands to this PSU - or if it's inadvisable. Suppose I could make an interface and try reading from my car's diagnostic socket :-) Andy
On Wed, 27 Jan 2021 at 13:08, Dave Cawley G4IUG <help@...> wrote:
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g4cch_1
Thanks Dave,
What's the upper and lower limit for voltage? Howard, g4cch
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Mike Willis
Hi Andy
That's what I did with an Arduino and a CAN bus adapter. Easy with all the libraries. E.g. google MCP2515 CAN Bus Module -- Mike G0MJW
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Mike Willis
E.g. this thread has some useful info http://www.thebackshed.com/forum/ViewTopic.php?FID=4&TID=12035
Here is some code as an example, #include <mcp_can.h>
#include <mcp_can_dfs.h>
#include <SPI.h>
unsigned char login[8] = {0x16, 0x36, 0x71, 0x07, 0x03, 0x76, 0x00, 0x00}; //this is for logging into your flatpack. Must use your serial number.
const int SPI_CS_PIN = 10;
MCP_CAN CAN(SPI_CS_PIN); // Set CS pin
#define VOLTAGE 4800
#define CURRENT 0100
uint8_t outset[8] = {CURRENT & 0xff, (CURRENT >> 8) & 0xff, VOLTAGE & 0xFF, (VOLTAGE >> 8) & 0xFF ,VOLTAGE & 0xFF, (VOLTAGE >> 8) & 0xFF ,0x3E, 0x17};
void setup()
{
Serial.begin(115200);
pinMode(3,INPUT);
START_INIT:
if(CAN_OK == CAN.begin(MCP_ANY, CAN_125KBPS, MCP_8MHZ))
{
Serial.println("CAN BUS Shield init ok!");
}
else
{
Serial.println("CAN BUS Shield init fail");
Serial.println("Init CAN BUS Shield again");
delay(100);
goto START_INIT;
}
CAN.setMode(0);
delay(200);
CAN.sendMsgBuf(0x05004804, 1, 8, login); // id = 1 so XX = 04
}
void loop() {
unsigned char len = 0;
unsigned char buf[8] ;
int c=0;
if(CAN_MSGAVAIL == CAN.checkReceive())
{
CAN.readMsgBuf(&len, buf);
uint32_t canId = CAN.getCanId();
Serial.print("0");
Serial.print(canId,HEX);
Serial.print("\t");
for(int i = 0; i<len; i++)
{
if( buf[i] < 0x10){ Serial.print("0");} Serial.print(buf[i],HEX);
Serial.print(" ");
}
Serial.println();
Serial.print("Temperature = ");
Serial.println(buf[0]);
Serial.print("Current = ");
Serial.println(buf[2]*255*0.1+buf[1]*0.1);
Serial.print("OutputVoltage = ");
Serial.println(buf[4]*255*0.01+buf[3]*0.01);
Serial.print("OutputPower = ");
Serial.println((buf[4]*255*0.01+buf[3]*0.01)*(buf[2]*255*0.1+buf[1]*0.1));
Serial.print("InputVoltage = ");
Serial.println(buf[5]);
//send request for new update
CAN.sendMsgBuf(0x05004804, 1, 8, login); // XX = 04
}
}
-- Mike G0MJW
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Neil Smith G4DBN
There are PICs with CAN bus interfaces on-chip, like the
PIC18F26K83
https://ww1.microchip.com/downloads/en/DeviceDoc/PIC18(L)F2526K83-Data-Sheet-DS40001943C.pdf
Some of the dsPIC33 family has CAN or ECAN on chip as well, for
example the £2 SOIC-28 dsPIC33EP64GP502
https://www.mouser.co.uk/datasheet/2/268/70000657H-277982.pdf
which is available in MPLab Express cloud IDE unlike the newer
dsPIC33EV64GM102 etc. I'm migrating all of my masthead and remote station control stuff to CANbus, but I got a bit bogged down in the software abstraction layers on OpenCAN. Some pushbike automatic gearchangers run CANbus, as I am informed
by a bike-mad chum. Neil G4DBN
On 27/01/2021 15:26, Andy G4JNT wrote:
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OK some
answers. But please
bear in mind my
original philosophy was to supply ready to go and tested 48V
PSU's and nothing
else. The price is £72.00 plus £10.00 postage in England, Scotland and Wales. I believe the range is 43.5-57.6V I have quite a few ! My setup is shown here and the data is attached Please do not ask me any questions, although the group may know. See my first sentence above again !Regards Dave G4IUG
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