Garland GI-MO/DU 7000, Service Manual

Part # 4526029 (02/22/11)

Page 6

Voltage Supply

The power board voltage supply is wired with the power 
contactor. On starting the generator, voltage is supplied to 
the power board. The transformer is connected directly at the 
entrance of the power supply. The transformer supplies two 
diff erent voltages: 230VAC for the power contactor and the 
fan as well as 23VAC for the low voltage supply. The 23VAC 
are changed on the circuit board C026 to 24VDC.

The following components are supplied with 24VDC:

• 

CPU-circuit board (C018)

• IGBT 

(C026)

• 

Fan relay (C014)

• External 

lamps

Power Board

As already stated, the power board is supplied by the power 
contactor. The mains current is measured by a current 
transformer, directly at the entrance of the 3-phases-rectifi er, 
After the rectifi er there is a direct voltage of 300V. The 
inductance that follows fi lters high frequency (EU) current .

At the following power switch (IGBT) an alternating current 
of approximately 20kHz is generated. This alternating current 
(coil current) is transferred to the induction coil. At the exit 
of the circuit board (C026), the coil current is measured by a 
current transformer. 

Control unit

The control unit is the heart of the generator. This is the CPU-
circuit board (C018) with an integrated microprocessor which 
manages the whole control system.

The following data are measured:

• Coil 

current

• Phases 

current

• 

Performance rate (Poti)

• 

Heat sink temperature (IGBT)

• Coil 

temperature

• Ambient 

temperature

The power switch (IGBT), the fan as well as the display are 
managed in response to these factors.

Display

Two elements are used for this display:

1.  LED-group (LED1 - LED8) on the CPU-Circuit board (C018)

2.  External lamps (24V), maximum 5 pieces

The fi ve external lamps are connected with the fi ve LED’s 
(LED1-LED5). Please distinguish between operation lamps 
and error lamps. The operation lamp shows what kind of 
operation for the respective fi eld:

• 

Lamp out: 

Field is cut out

• Lamp 

fl ashes briefl y 

Pan detection (pan is searched)

• Lamp 

fl ashes an error code: 

Error message (see Error 

Messages table)

• 

Lamp continuously on: 

Power on

The error lamp indicates an error function.

LED1 to LED4 lead to external lamps on the outside, they are 
used as operational lamps or as error lamps, depending on 
the generator type. If an operation lamp or an error lamp is 
shared by two fi elds (for example the surface covering this 
induction type) the display can be overwritten from another 
fi eld. As far as the error code display is concerned, the lower 
fi eld has priority.

LED5 lead to the outside for an external lamp also. This is the 
general error lamp for all fi elds all the time.

In an error, LED6 to LED8 show the error code, but only until 
error code 7. If this happens in some errors, the lower fi eld 
and the lower error code have priority.