Changing original 32Amp contactors for solid state relays?

[marconi]

If you want to measure total power provided by the 3 phase 3 wire supply to all the UFH connected to a panel then use two meters as I showed in my second diagram ie: place the two meters between the main switch and the contactors. The input to one meter is L1-N and to the other L2-N.

If you want to measure the power consumed by an individual UFH zone (effectively a single phase circuit) then use my first diagram ie: place the PM between the output of the contactor and the UFH zone. The input will be one of these pairs L1-N, L2-N or L1-L2.

Be careful to use the correct terminals on the PM ie: Lin, Lout, Nin and Nout (though it is most likely Nin and Nout are the same node so it is immaterial which is in and which is out.

I cannot turn up the spec for the DM25S - do you have it?

If you wish we can arrange a zoom session if that would be easier for you.

Regards

Marconi

 

[Yonny24]

Sorry just posted and saw your post above as I'm reading through it now.

Perfect many thanks again.

I'll go for set up #2. 2 power meters between the CBS and contactor. Just need the total for all.
So my figures for the UFH#1/#2 are incorrect as I do not have L2 connected even though the PM shows some power feeding through it, possibly just a % of the total power. Did suspect the street side new meter was reading more KwH than I calculated when running the UFH upstairs. Downstairs is pretty much spot on.

Will purchase another PM.
[automerge]1595451726[/automerge]
I have found these specs (mine is the 40 amp version).

Model Number:
DM25S
Display Type:
Digital Only
Phase:
Single Phase
Measuring Energy Range:
0-99999
Accuracy Class:
Class1
Output Voltage:
220VAC,110VAC
Operating Temperature:
-25℃~+55℃
Dimensions:
DIN EN50022 Standard
Product Name:
Meter Energy
Width:
18mm (One Module)
Current Specification (A):
5(20),5(30)A,5(40)A
Frequency:
50-60HZ
Constant:
2000imp/kWh
Display Mode:
5+1 Digits Counter Display
Connection Mode:
Direct Mode
Standard:
IEC60253-21

 

[Yonny24]

Sorry just posted and saw your post above as I'm reading through it now.

Perfect many thanks again.

I'll go for set up #2. 2 power meters between the CBS and contactor. Just need the total for all.
So my figures for the UFH#1/#2 are incorrect as I do not have L2 connected even though the PM shows some power feeding through it, possibly just a % of the total power. Did suspect the street side new meter was reading more KwH than I calculated when running the UFH upstairs. Downstairs is pretty much spot on.

Will purchase another PM.
[automerge]1595451726[/automerge]
I have found these specs (mine is the 40 amp version).

Model Number:
DM25S
Display Type:
Digital Only
Phase:
Single Phase
Measuring Energy Range:
0-99999
Accuracy Class:
Class1
Output Voltage:
220VAC,110VAC
Operating Temperature:
-25℃~+55℃
Dimensions:
DIN EN50022 Standard
Product Name:
Meter Energy
Width:
18mm (One Module)
Current Specification (A):
5(20),5(30)A,5(40)A
Frequency:
50-60HZ
Constant:
2000imp/kWh
Display Mode:
5+1 Digits Counter Display
Connection Mode:
Direct Mode
Standard:
IEC60253-21

My previous drawing of the power meter was incorrect. The middle output of the CBS is the N feeding to the middle 2 inputs of the contactor.
I have swapped the power meter over to the other live and neutral to measure ufh 1 and 2 for now.

 

[Yonny24]

I suspected measuring the UFH #1 and #2 with the PM wired connected to L1 and N (as opposed to L2 and N) the Kwh is double than previously measured.

 

[Yonny24]

Left hand drawing is the proposed wiring for the 2 x PM's. With the N line going in and out of both power meters. is this correct according to your diagram? Right is original wiring.

Thanks

 

[marconi]

Yours will work but it is simpler to do it like my attached diagram. Add the wire I have indicated in blue to go to the link between the middle terminals of the CTR and remove the two I have indicated in white.

(A power meter needs to know the voltage which it obtains from the two inputs and the current flow between the line input and line output. This why we can dispense with the white wires.)

 

[Yonny24]

Yours will work but it is simpler to do it like my attached diagram. Add the wire I have indicated in blue to go to the link between the middle terminals of the CTR and remove the two I have indicated in white.

(A power meter needs to know the voltage which it obtains from the two inputs and the current flow between the line input and line output. This why we can dispense with the white wires.)

Many thanks Marconi.

I think I will do the same with the downstairs wiring. 2 x powermeters between the main CBS and contactors (currently have 3 after the 3 contactors). I really only need to measure the total going through the 3 phase wiring now. This way I can re-use one of the 3 PM's I have and install it upstairs. So I'll have 2 downstairs and 2 upstairs. Makes the wiring a bit neater also.

Have a good weekend

 

[Yonny24]

Many thanks Marconi.

I think I will do the same with the downstairs wiring. 2 x powermeters between the main CBS and contactors (currently have 3 after the 3 contactors). I really only need to measure the total going through the 3 phase wiring now. This way I can re-use one of the 3 PM's I have and install it upstairs. So I'll have 2 downstairs and 2 upstairs. Makes the wiring a bit neater also.

Have a good weekend

All completed this weekend. 2 power meters installed between the CBS and contactors downstairs and 2 upstairs. Working Perfectly.

Thank you very much Marconi!