MEDC DB3 Manuel Technique page 2

English
1. INSTALLATION
1.1 Mounting
The unit mounts via a 'u' shaped strap. The fixing centres of the strap are quoted on the catalogue sheet. When
fixed in position the units' alignment can be adjusted by loosening the two M6 screws, which fasten the strap to
the sounder. The sounder can then be adjusted to the required position and the screws tightened. The sounder
should be positioned such that dust/debris or water cannot settle in the re-entrant horn.
1.2 To Remove End Cover
Remove the 6 off M5 cover screws (EExd version) or 2 off M5 cover screws (EExde version).
1.3 Wiring
Cable termination should be in accordance with specifications applying to the application. MEDC recommend
that all cables and cores should be fully identified.
Ensure that only the correct certified glands are used and that the assembly is shrouded and correctly earthed.
The unit is available in six basic configurations: -
1. EExd DC Input Single Tone
2. EExde DC Input Single Tone
3. EExd DC Input Dual Tone
4. EExde DC Input Dual Tone
5. EExd AC Input
6. EExde AC Input
Types 1. and 2. have 6 terminals labelled as T1 to T6. The supply should be connected to T1(+ve), T3(-ve), loop
out on T4, T6 respectively.
Types 3. and 4. have 6 terminals labelled as T1 to T6.
For a 2 wire system, the supply should be connected to T1(+ve), T2(-ve), loop out on T4, T5 respectively, alter-
natively an EOL resistor can be connected to T4, T5.
For a 3 wire system, the supply should be connected to T1(common +ve), T2(-ve 1), T3(-ve 2), loop out on T4,
T5, T6 respectively, alternatively an EOL resistor can be connected to T4, T5 or T4, T6.
Type 5. has 4 terminals labelled L, L, N, N.
The supply should be connected to L, N, loop out on L, N.
Type 6. has 6 terminals labelled as T1 to T6.
The supply should be connected to T1(L), T2(N), loop out on T4, T5 respectively.
1.4 General
When installing and operating explosion-proof electrical equipment, the relevant national regulations for instal-
lation and operation (e.g. IEE Wiring Regulations) must be observed.
Ensure that all nuts, bolts and fixings are secure.
Ensure that only the correct certified stopping plugs are used to blank off unused gland entry points. We recom-
mend the use of 'HYLOMAR PL32 COMPOUND' on the threads of the stopping plugs in order to maintain the
IP rating of the unit.
2.0 OPERATION
The sounder is available in various AC input voltage versions and a single DC voltage input version.
For AC versions, the supply voltage tolerance is +10%.
For the DC version, the absolute input voltage range is 11.0V to 58.0V.
The DC version can be operated as a dual-tone unit, switching between the two tones by either: -
(a) Reversing the polarity of the supply (2 wire)
02/08 © MEDC 2003