3 Product description
17
BA5789879-01 EN
The pressure relief device is available with various tripping pressures.
Type
Tripping pressure
[psi]
[bar]
[kPa]
LMPRD 4 psi
4 ± 1
0.28 +/- 0.07
28 +/- 6.9
LMPRD 6 psi
6 ± 1
0.41 +/- 0.07
41 +/- 6.9
LMPRD 8 psi
8 ± 1
0.55 +/- 0.07
55 +/- 6.9
LMPRD 10 psi
10 ± 1
0.69 +/- 0.07
69 +/- 6.9
LMPRD 12 psi
12 ± 1
0.83 +/- 0.07
83 +/- 6.9
LMPRD 15 psi
15 ± 2
1.03 +/- 0.14
103 +/- 13.8
LMPRD 20 psi
20 ± 2
1.38 +/- 0.14
138 +/- 13.8
LMPRD 25 psi
25 ± 2
1.72 +/- 0.14
172 +/- 13.8
LMPRD 30 psi
30 ± 2
2.07 +/- 0.14
207 +/- 13.8
Table 4: Pressure range
3.3 Design/versions
The pressure relief device consists of a device flange with valve, spring as-
sembly, signal pin and protective cover; as an option also with 1 or 2 micro-
switches and with semaphore.
The design and the designation of the key device components are to be
found in the following drawings:
▪ Pressure relief device with standard protective cover [
▪ Pressure relief device with OD protective cover [
O
il
D
irected = with directed oil flow)
The device flange of the pressure relief device is mounted with a mounting
seal tight on the counter flange of the transformer tank or the on-load tap-
changer cover. A spring assembly presses the valve plate against the seal
seat, which consists of one axially aligned and one radially aligned sealing
lip. The spring assembly is tensioned between a counter bearing and the de-
vice flange with 6 fixing screws.
Summary of Contents for MESSKO MPREC
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