Mach LED 2
MC/SC
Dr. Mach
Lamps and Engineering
59160001-MCSC
Edition 06
08.05.2013 / Bak page 16/34
Information about the power supply
The Dr. Mach LED lights need a direct current voltage of 24V-30V DC for correct operation. The undula-
tion of the direct current voltage should not exceed 5%. The LED control inside the light is current-
operated, that means that a change of the supply voltage does not lead to a change of the light intensity.
Due to the fact that the power requirement of the light is constant, an increase in the supply voltage
means a decrease of the total current of the light and therefore to a decrease of the heat development
inside the light. That is why it is recommended to supply the light with a high voltage, so the life span of
the component parts is not shortened by an exceeding heat development.
The control electronics of the light has an initial voltage at starting of approx. 17V. This voltage value is
too low for the light operation. The light can be operated with 20V DC for a short time, but in this case the
heat development will be very high, which has a negative influence on the life span of the component
parts. The initialisation phase of the control electronics is approx. 1 second. In case that the supply volt-
age does not reach 24V-30V within this second, the cluster board of the lights can be damaged. This is
the reason why a soft start, which makes sense for halogen lights, is not allowed for LED lights.
The capacitances inside the light and the LED control cause quite high current peaks when turning on the
power supply. The current peaks are in the range of the sevenfold rated current. A current limiting and a
protection of the lights should not delimitate the current peak, because the electronic boards would even-
tually consider this delimitation as a failure in power supply and would change to emergency operation
mode. The emergency operation mode does not ensure a normal functionality of the lights and must be
avoided.
Swapping the polarity at the LED light does not lead to a malfunction. After the polarity is changed, the
light works perfectly. A wrong polarity can happen by swapping the wires inside the spring arm, horizontal
arm or ceiling flange tube, but also inside the transformer housing or the light. The error code for wrong
polarity on the light display is C0--. The display is on, but the light is not working. If the polarity is swapped
only at one of the lights and the lights are equipped with communication, caution is advised when chang-
ing the polarity at the ceiling flange. If the polarity at the power supplies is correct and the polarity on the
ceiling flange is changed only for one light, it may happen that due to the bridge between the 0V lines of
the power supplies the 28V line of one power supply is connected to the 0V line of the other power sup-
ply. The function of the lights is OK, the connection of the power supplies is not. The power supplies are
working one against the other.
Troubleshooting
If a communication error on an installed system must be found, first of all the neutral point,
where all communication lines are connected, must be disconnected.
The disconnection must
be done only after the primary supply voltage was turned off.
On the free lines the open-
circuit voltage must be checked. After switching on the supply voltage all displays must work
and the voltage measured on every communication line must be 5V-6V. The voltage is meas-
ured with the OV line of the power supplies (normally the blue terminals on the flange).
If the measured voltage is not correct (i.e. 1V), the communication pin is damaged and the con-
trol board of the light must be exchanged. If the measured voltage is 0V, the line is not connect-
ed to the communication pin of the control board.
If the measured voltages are correct, please connect first of all the communication lines of the
lights and check their correct function. If there is a wall panel on site, do not connect it yet to the
communication line. Transmit the values of one light to the other lights and check the function. If
the communication is not working, the malfunction must be located in the light attachment. In
order to resolve the problem, the spring arms, the horizontal arms and the ceiling tube cables
must be changed individually and one after another.
If the communication between the lights is working, the wall panel can be connected and the
function can be tested. If the communication is not working, please check the connections in the
wall panel and the settings of the DIP switches. Please look also for damaged crimp connec-
tions, where single strands can cause a short circuit.
