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PeeCeeBee PSU GB

Thx Shaan your info.
Not sure the problem is the PSU w/o connect any other board to incur it.
Also I found two in series with relay resistor so hot, therefore I ordered 24v relay replace it.
So the new resistor value could be got 0.3W exhausted to sustain the temperature in long run. You can consider update the guide, if person need a rail voltage above 40v, they should better deploy 24v or higher voltage that relay supported😁
 
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Hi shaan,

Any problem using this Omron relay. Rated at 12V. ? See piuc attached.

Relay1.jpg
 
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Hi shaan,

A little confused when looking at the datasheet for the G2R-1-E-T130-DC12 relay to find the correct coil resistance to calculate the resistor value.

Is this relay the 12V DC bi-furcated contact form where the coil resistance is 275 ohms (note: there is no "Z" classification in the model number to indicate this) or is the relay the 12V AC single contact form where the coil resistance is 65 ohm. I think the latter 65 ohm is correct, but want to check.

Note: On the Mouser website the coil resistance is listed as 275 ohms in their details, so I am confused

Can you clarify this for me?

Thanks for the help
 
Hi shaan,

A little confused when looking at the datasheet for the G2R-1-E-T130-DC12 relay to find the correct coil resistance to calculate the resistor value.

Use one 330ohm and one 470ohm, both 2watt, on each side.

Is this relay the 12V DC bi-furcated contact form where the coil resistance is 275 ohms (note: there is no "Z" classification in the model number to indicate this) or is the relay the 12V AC single contact form where the coil resistance is 65 ohm. I think the latter 65 ohm is correct, but want to check.

Note: On the Mouser website the coil resistance is listed as 275 ohms in their details, so I am confused

In the picture you shared there is clear 12VDC marking on the relay. So I think 275ohm is correct. You can also directly measure the coil resistance with the meter. Now the formula gives a value close to 400ohm for each of the resistors. So to make it 800ohm total, 330 and 470 is at our disposal.
 
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Thanks for the info shaan,

I will be using 56V rails, the resistor calculation works out to be 504 ohms, (unless I am not calculating correctly),so a total of 1008 ohms. Based on this, when I put in my last order for parts, I ordered 4 x 510R /1W resistors ohm for the psu's according to the calculations and wattage recommended on the schematic. Are you now saying that I need 2W resistors rather than 1W resistors?

Thanks for the clarification, don't mean to be a pain, but every time something changes, a new shipment has to be made at a minimum shipping charge ($10 - $30 usually) unless you order over $200 worth of parts for free shipping. Adds up over time.
 
You calculated for 56V rails and I for 50. Your calalculation is fine.

With 44V across the resistors they'll dissipate close to 1W each, so they'll be quite warm during operation. Solder them with one end as close as possible to the pcb. This will keep some of the heat away.
 
Going to use 625VA transformer with two PSUs of each rail voltage being 60VDC. What size and what type of fuses to use? Schematic says it's 10A. 625VA / 60 = 10.4999 But my amp has two psus so should I use more than 5A(=10/2). And slow and fast? I use mains inlet with fuse in it. What size of fuse will be needed for mains inlet? Thanks.
 
@shaan , out of interest, can we use NTC thermistors in place of R1/R2? What rating would you recommend for 150VA transformer with 2 x 28V AC = nearly 40V DC rails?
R1 & R2 are current limiters right? Just wondered if NTCs would be suitable - NTC 5D-15 Inrush Current Limiter

I have 3A FB fuses for the rails.

Nearly finished my 50W AEM6000 build using your PSU, James Transformers messed up the secondary voltages on a transformer they sent, so will be a while yet unfortunately.

IMG_0560.JPG IMG_0561.JPG
 
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