Automatic Power Reduction Table - Hitachi EC702HP Operation Manual

Section 4 - Initial Activation (ATSC Transmitters)
B – Super-Excitement
If an excessive increase in the value of the excitation signal level occurs, the control, through the
ALC, will interact with the excitement, to maintain a constant output power in it's rated value.
C – Variations in the network
Each piece of equipment has its own independent power supply, all of which have equal protection
features.
- Protection against short circuit
- Surge Protection
Basically, the surge protection on the network is performed by inserting the varistors between
phases and between phase and earth, thus absorbing peak voltage, not allowing them to damage
the power source. Protection against short-circuit is carried out by monitoring the current in the
output of the power source. If the current exceeds a pre-set reference value, it will understand
that the source output is shorted and should be disabled through the shutdown pin.
4.3.5 Transistor Temperature Setting
The default temperature value of the transistor is 60 ° (140 ° F), factory set, the hottest transistor
will be the reference. The temperature can be set between 50 and 60 ° in the Setup Menu "PA
Temperature Control" (Setup Menu [1M00]). This setting can be changed according to ambient
temperature and transmitter efficiency. You can change this setting by following the procedure
below:
- With the transmitter in the operating power for at least 30 minutes, access the web page of the
transmitter or the USB interface of the power drawer and check the rotation of the fans. Fan
rotation should be between 2000rpm and 7000rpm.
- After checking all fans of all drawers and if the highest rotation is below 5500rpm, the control
temperature can be reduced, it is advisable to reduce in steps of 2 degrees.
- Set the transistor temperature in the "PA Temperature Control" Setup Menu. Once the fan
speed is set, you should wait a few minutes until the transistor temperature stabilizes at the set
value, then check the fan speed again, operation will be between 5500rpm and 6000rpm.
4.4

Automatic Power reduction Table

In case of any defect or failure to communicate in one or more Power Drawers, the equipment
will continue running, but on condition of power reduction. The reduction table of each equipment
of the E-Compact series is calculated according to the following formula:
In this condition, the equipment will operate with a power reduction alarm and with other alarms
that identifiy which of the drawers are not operating and the reason of it.
The EC701HP transmitter uses reduction table for modules. Below the formula for calculating
table:
*PAs - Power Amplifiers
Manual Rev. 0.0 - April 2016
4-11