User's Manual

AT71-250 Transmitter Owner’s Manual

MOD 3886 - Technical Specifications:

Parameter

Specification

Supply Voltage

+50V

Switching Frequency

125kHz

Nominal Output Voltage

+50Vdc and +24Vdc

MOD CIM 3917: Power Supply for the auxiliary bank of fans

This module is a DC / DC converter of +50 Vdc to +24 Vdc, which feeds the bank of auxiliary fans of

the drawer GV 4790. It can provide up to 3A. Furthermore, has a PWM circuit that regulates the

output voltage at seven different steps, resulting in seven operations speeds avaliable for the bank of

fans. This PWM circuit is controlled by software that monitors the junction temperature of the

transistor and chooses the best rotation of the fan at that temperature.

MOD VENP 4893: Front side bank of fans.

This module is the bank of fans locates on the front side of the drawer. It is comprised of four fans

120mm x 120mm/+24 V, which operate in seven different speeds, depending on the junction

temperature of the transistor.

MOD VENP EXT GV 4790: Auxiliary Bank of Fans.

Bank of fans helping fans composed of 2 x (80mm x 80mm)/ +24 V, operating in

7 different speeds, depending on the junction temperature of the transistor.

Cooling System

The transmitter refrigeration is obtained by forced air ventilation via fans located inside the drawer GV

4790. The cooling system promotes circulation of air inside thereof.

The front and back panels with ventilation holes also aid in refrigerating the transmitter, allowing

direct exit of air from the device to the environment.