Garland 7000 service manual Voltage Supply, Power Board, Control unit, Display

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 different 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-rectifier, After the rectifier there is a direct voltage of 300V. The inductance that follows filters 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 five external lamps are connected with the five LED’s (LED1-LED5). Please distinguish between operation lamps and error lamps. The operation lamp shows what kind of operation for the respective field:

• Lamp out: Field is cut out

•Lamp flashes briefly Pan detection (pan is searched)

•	Lamp flashes 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 fields (for example the surface covering this induction type) the display can be overwritten from another field. As far as the error code display is concerned, the lower field has priority.

LED5 lead to the outside for an external lamp also. This is the general error lamp for all fields 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 field and the lower error code have priority.

Page 6 Part # 4526029 (02/22/11)