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Jordo  
#1 Posted : Tuesday, March 20, 2012 2:13:06 PM(UTC)
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Hi Guy's,

I finally received the transformers I was waiting for.
I just hooked up the Placids (2x HDBP, 2x HD)

One of the HDBP's is running warm on it's cooling elements while there is no load connected to it.

I measure 0,25V over TP_VIN- and TP_CCS- and 0,29 over TP_VIN+ and TP_CCS+

Is it shorted somewhere?

Best regards,

Jordo
Brian Donegan  
#2 Posted : Tuesday, March 20, 2012 2:15:39 PM(UTC)
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No, that is normal. Shunt regulators shunt away extra current as heat.
Jordo  
#3 Posted : Tuesday, March 20, 2012 2:21:17 PM(UTC)
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Ok, but the others don't...
Could it have something to do with the start values of the VR-1 or so?
Brian Donegan  
#4 Posted : Tuesday, March 20, 2012 2:27:21 PM(UTC)
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Are they shunting any current?
Jordo  
#5 Posted : Tuesday, March 20, 2012 2:28:29 PM(UTC)
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No they don't...

If I meassure between VIN and CCS.

Just to be clear; Nothing is connected to the Placids and only one of the HDBP's is running warm/hot. (When I feel with the back of my fingers it begins to feel hot).

Edited by user Tuesday, March 20, 2012 2:40:54 PM(UTC)  | Reason: Not specified

Russ White  
#6 Posted : Tuesday, March 20, 2012 8:19:26 PM(UTC)
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You are making the shunt transistor shunt all of the CCS current. You should be supplying a load to take most of that current. :)
Jordo  
#7 Posted : Wednesday, March 21, 2012 1:39:54 AM(UTC)
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Ok I think I got it now.
Ivé opened the Shunts just to supply some 0,2V = 200mA.
I let them all become a bit warm and than I will adjust the HDBP's to 12VDC and the HD's to 2,25VDC.

After that it must be safe to connect the components :)

Thx!

Jordo
Jordo  
#8 Posted : Wednesday, March 21, 2012 3:55:01 AM(UTC)
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Let me see if I get this straight before toasting my precious DAC Anxious

The HDBP's have the IVY's connected and the Ventus EZ.
These draw respectively 150mA + 250 mA.
If I add this I have to adjust the CCS current with VR1 over TP_VIN to 4,0 VDC.

For the RH Placid I have the DAC (440mA) + Sidecar (65 mA) + 4:1 Mux (30 mA) = 535 mA
So I have to measure 5,35 VDC over the CCS and TP_VIN

For the LH Placid I have the DAC and the Toslink module connected.
Wath shall I account for the Toslink module?

I also can choose (reccommended?) to power the IVY's with 15VDC.
Than the current drops to 90mA.
I think it would be best to keep the safe factor of 5% in mind and aim for a 14,25VDC out of the HDBP.
But what will be the reccommended shunt setting in that case assuming that the current will also drop for the ventus when raising the voltage?


Am I getting this right this way?

Edited by user Wednesday, March 21, 2012 4:16:54 AM(UTC)  | Reason: Not specified

LeonvB  
#9 Posted : Wednesday, March 21, 2012 11:58:46 AM(UTC)
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Please divide all voltages you mentioned by 10, and measure the amount of current being shunted: "To measure the current being shunted measure the voltage between TP-OUT and TP-SHUNT"
Manual clearly states 1mV = 1mA. Please adjust to a shunt current of around 50-60mA.
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