Jands HP6, Technical Manual

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Equipment Description 3-2
Revision 2 - 26 April, 2000 HP SERIES DIMMER TECHNICAL MANUAL
DELTA SUPPLY OPERATION (ILLEGAL IN MOST COUNTRIES!)
The available venue mains supply in some countries (eg. the Phillipines) is in the form of
three phases (220 volts between phases) with no neutral connection. The dimmer may be
configured for operation from 220V delta supplies.
The bridge between the three neutral terminal poles (N1, N2, N3) must be removed
before the three incoming active lines are connected.
•
The first incoming active is connected to terminals A1 and N3.
•
The second incoming active is connected to terminals A2 and N1.
•
The third incoming active is connected to terminals A3 and N2.
Note that this connection is ILLEGAL in Australia, Europe and the U.K. since this
connection renders the output sockets' neutral pins LIVE.
Note that a dimmer wired in this fashion will be subjected to CONTINUOUS OVER-
VOLTAGE if connected to the 415V wye or star three-phase supply of most countries.
3.1.2 Mains Radio Frequency Suppression
Radio-frequency interference generated by phase-controlled dimming is heavily
attenuated before it can contaminate the mains supply.
Capacitors C1, C2 and C3 (1uF 275VAC X2 rated) are connected from each incoming
active (A1, A2, A3) to the corresponding neutral (N1, N2, N3).
Capacitors C14 thru C19 (4700pF 275VAC Y2 rated) are connected from each incoming
active and neutral to ground.
The mains circuits are protected from (improbable) catastrophic failure of these
capacitors by fusible PCB track links (labelled FL1 thru FL4). Failure of these links will
remove power from the low-voltage transformer associated with that phase. The links
may be renewed during repairs by wire links (a single strand of flexible wire, not more
than 0.2mm dia).
3.1.3 Neutral - Earth Voltage Detection
Voltages of more than 15V (AC average) between neutral and earth are a strong
indicator of mains supply problems (eg missing or weak neutral connection, or missing
earth).
The voltage from the dimmers' earth to each of the three neutrals is sensed by three 100K
resistors (RG1, RG2, RG3), full-wave rectified and fed to the input LED of an
optoisolator.
When the dimmer is configured for normal three-phase star connection, the three
incoming neutrals are bridged, yielding an impedance of 33K from neutral to ground and
a sensitivity of 15V AC average.
If the dimmer is configured for three same-phase inputs, each neutral has a sensitivity of
45V (or 15V for all three neutrals).
If the dimmer is configured for delta operation (with no incoming neutral) the circuit will
detect when the "centre average" of the three phases deviates more than 15V from earth.