OSRAM POWERTRONIC PT-FIT I ECG for HID lamps, with cable clamp - Manual (Page 17)

THE PRODUCT IN OPERATION
Easy ways of increasing the number of ECGs per circuit
breaker:
• Use of the EBN-OS inrush current limiter
• The use of AC relays for each group with the maximum
permissible number of ECGs. These relays should be
connected so that they close as soon as mains voltage
is applied. The retardation of the relays will cause the
inrush current for the 2nd group to occur with a delay as
compared to the 1st group. The switch-on peak current
value is thus effectively reduced into a number of smaller
successive fl ows.
2.2.6. Leakage current, protective current, contact
current, earth leakage circuit breaker (ELCB)
According to current luminaire standards, the term leakage
current includes both the concept of contact current and
protective current.
The internal interference suppression fi lter in the ECG and
the lamp cable near earthed surfaces cause a leakage
current through the earth protection cable in Class I lumi-
naires. The strength of this leakage will depend on the
type of the affected device.
All POWERTRONIC ® ECGs with a consumption of < 4 A
have a substantially lower protective current than the
maximum permissible value of 2 mA (rms).
Just like in the case of the inrush current, the protective
current limits the number of ECGs to the number that can
be operated on a leakage current circuit breaker.
The following solutions can be suggested in order to
increase the number of devices:
• Distribute luminaires across 3 phases and use
3-phase RCDs
• Use surge-current-resistant short-delay RCDs
• Use RCDs with 30 mA (where permissible)
• Connect max. 30 ECGs per phase and RCD
The contact current is restricted for all POWERTRONIC ®
ECGs to 0.7 mA
peak
, or 0.5 mA
rms
.
2.3. Behavior in operation
2.3.1. Lamp ignition and lamp operation
The operation of high-pressure discharge lamps is divided
into a start-up phase and a running phase, each of which
involve very different behaviors. During the start-up phase
a voltage range of 1,800 to 4,000 V (depending on the type
of lamp) is required for the initial ignition of a high-pres-
sure discharge lamp. During normal running, voltages of
80 to 140 V are required, depending on lamp type and age.
In order to enable the safe and reliable start-up of the
lamp, POWERTRONIC
® ECGs provide a short burst of ig-
nition voltage of up to 4.5 kV for lamp start. As the ignition
process is asymmetric in structure, the strong potential is
supplied through the LH terminal marked with the lightning
bolt inside a triangle.
17
The intelligent POWERTRONIC ® ECG monitors each phase
of the start-up process and, as soon as the lamp has
reached stable operating mode after going through what
is referred to as the "breakthrough" stage, reduces the
voltage to the required value for normal lamp working.
2.3.2. Hot restrike of lamp
POWERTRONIC
® ECGs are not capable of igniting high-
pressure discharge lamps when they are hot.
For example, for a metal halide lamp that requires an
ignition voltage of up to 4.5 kV cold, the required voltage
will increase to 30 kV in a hot state.
Progressive cooling of the lamp will bring this value back
down. Depending on the lamp's wattage, the luminaire
structure and the cooling conditions for the lamp inside
the luminaire, high-pressure discharge lamps return to a
level in between 3 and 20 minutes in which they can be
ignited once more by the ECG, with the maximum of
4.5 kV available to it.
In order to re-ignite double-ended metal halide and NAV
lamps from a hot state, special hot restrike devices and
special socket designs are required. In addition to this,
the approval of the lamp manufacturer confi rming the
suitabi lity of the lamp is also a precondition for this.
2.3.3. ECG reset, restart
If a POWERTRONIC
® ECG should switch off (e.g. due to
an ignition timeout, temperature-related cutoff, etc.) then
it must be disconnected from mains power for at least
0.5 seconds before it can be switched on again.
2.3.4. Constant lamp wattage
As compared with conventional control gear, a
POWERTRONIC
® ECG supplies its high-pressure dis charge
lamp with constant wattage over the whole of the lamp's
service life. The fl uctuation range is within a maximum of
5 %. The increase in the lamp working voltage over the
service life of the lamp is regulated via the lamp current
supplied by the ECG.
In contrast, with a conventional control gear the system
wattage may fl uctuate quite substantially, as it is not
possible to regulate the lamp voltage.
For more information on this topic, see also the applica-
tion paper:
"Metal halide lamps" – hints on application and use"