Solid State HF Welder / High-output Solid-state Welders Solid state H.F welder is specially designed for straight seam welding. It adopts high power components of US IR IRFP460 MOSFET and Germany IXYS Company DSEI60-06A rapid recovery diode.The high power capacitor C and inductor coil L compose current-mode parallel upper-voltage resonance circuit, which doesn’t need output transformer. Thus, it not only improves the efficiency, but also increases the reliability of the welder. The solid state H.F welder has such distinct features as energy-saving, effective welding, simple structure, easy maintenance, low failure rate, low maintenance cost etc. ? Process of HF Welder on ERW Pipe Mill: ? Spec:

Type	QGT-1-600
Input rated power	900KVA
Output rated power	600KW
Input rated voltage	3φ 380V
Input rated current	1519A
Rated DC voltage	235V
Rated DC current	3000A
Frequency range	300KHZ
Efficiency	>85%
Power factor ( Full load )	≥0.9
Cooling water pressure	0.15-0.3MPa
Cooling water flow	>47m3/h
Input water temperature	<35℃
Resonance method	Series-parallel Complex resonance

? ? ? ? ?Supply List:

DESCRIPTION	COMPOSITION	QTY.
QGT-1-600KW Solid State H.F Welder (one unit)	DC Power Unit	1
	Inverter Output Unit	1
	Central Control Unit	1
	Water-water Heat Exchange Unit	1
	Rectifier isolation transformer	1
	Air conditioner	1 set
	Output Leg	1

? Performance introduction of the QGT-1 series solid state H.F welder 1 DC Power Unit
DC Power Unit includes rectify, flight wave and control parts. 3-phase full-controllable thyristor rectifying bridge and flight wave reactor, flight wave capacitor, and filter ensure stable DC output and guarantees high quality welding.?
Current meter, voltage meter and control system are equipped in the DC power unit. Thus the welder is controllable even without central control unit.
Output DC voltage 0-235V is continuously adjustable and has soft start and time constant setting.
2 Inverter Output Unit
The inverter part is made up by MOSFET single phase invert unit connected in parallel. The power of each pair of units is 50KW. The pairs of units adopt the building block method to realize power superposition (from 50KW to 1000KW). Each unit has self-diagnostics ability. All the design is to ensure easy installation and maintenance.
Automatic load matching system ensures the most efficiency and lowest mill cost. Furthermore, the welding transformer is not needed.
The protection circuits are specially designed. It can ensure the stability and safety of the welder, even in open and short circuit condition. Also it can afford coils arcing to reduce mill stop. 3 Central Control Unit
Installed with LCD, power and speed adjust module; indicate the output current and voltage of the DC power unit; armature voltage and current, excitation voltage and current of the DC speed adjust unit. The pipe line can be completely controlled by the central control unit. 4 Water-water Heat Exchange Unit
Composition:Plate heat exchanger, water tank, pump and electrical control part.
Working principle: The internal cooling is called inner water (distilled water), and the external cooling is called outer water (ordinary water). External and inner water exchange through the plate heat exchanger to reduce the temperature of the inner water. Thus, the equipment inside is cooled.
Features:
A. Seal circulation, outer water (normal) cools down the inner water (distilled water), no scaling.
B. High efficiency of heat radiation, low cost, applicable to large power H.F equipment.
C. Reservoir is used for outer water. 5 Rectifier isolation transformer
It is the input rectifier part of the equipment. It reduces the input voltage from 415V to 200V to ensure stable power supply, at the same time, to insulate the power grid. ? Complete protection and easy maintenance Equipment has perfect failure alarm and fault display system. Once there is a failure, the LCD can show the fault location clearly, so that maintenance personnel can quickly find out the cause of the failure and troubleshoot.
Protection measures as follows:?
Current protection:Once coil short circuit or over-current caused by disoperation occurs,the device will automatically stop and display the fault.?
Open-circuit protection:Once open-circuit caused by disoperation occurs, the device will automatically stop and display the fault.?
Lack Phase protection:Once any phase of the three-phase power supply loses, the device will automatically stop and the LED of the rectify unit lights up.?
Wrong Phase protection:?Once wrong wiring occurs, the equipment cannot start.
Module board protection:
A. Once the temperature of the oscillation component on module board is above 60 ℃, the device will automatically stop.
B. Once the working voltage of module board is lower than the setting value, the device will automatically stop.
C. Once the trigger pulse loses, the device will automatically stop.
D. Once MOSFET damaged,the device will automatically stop.
Water pressure protection:?Once the water pressure is insufficient or lower than the setting value, the device will automatically stop and display the fault.
Water temperature protection:?Once the temperature of circulating water is higher than the setting value, the device will automatically stop and display the fault.
Frequency Protection:Once frequency is too high or too low, the inverter trigger unit LED lights up and the rectify unit is switched off. ? Control board functions and protection technology: Main control board: ? +12V,-12V,24V are power supply instructions.
L2----when main circuit is power on, meanwhile the initial start voltage is established, L2 lights up.
CX----wrong phase protection indication(convenient for commission setting).
GL----over current protection indication. When DC current is over the rating value, GL lights up. Inverter control board: GY----over voltage protection indication. When output voltage is too high and the inductor is open circuit, GY lights up.
DC----when the voltage of inverter control board is low, DC lights up.
MOD----power module board failure, MOD lights up.
FBH----frequency protection indication. When inductor is open circuit, coils are short circuit, the inductor arcing, poor insulation of output plate, or failure of tank capacitor, FBH lights up.
LF----when operating frequency too low, LF lights up.
HF----when operating frequency too high, HF lights up. Power module board:
The power board is divided into “module+” and “module-”. The apparent difference is the color of the coils. The red is “module+” and the black is “module-”. When remove or replace the power board, be careful not to make mistakes.
The power module board has protections as follows:
A. Once the temperature of oscillation component on module board is above 60 ℃, the device will automatically stop.
B. Once the working voltage of module board is lower than the setting value, the device will automatically stop.
C. Once the trigger pulse loses, the device will automatically stop.
D. Once MOSFET is damaged, the device will automatically stop. ? Main parts list of QGT-1-600KW solid state HF welder: ? ?

S/N	Description	Specification	Manufacturer
1	Power module board	60KW/pair	?
2	MOSFET	IRFP460	US IR
3	Fast recovery diode	DSEI60-06A	Germany IXYS
4	Power resistors	25Ω/35W	EBG
5	Thyristor	KP2000A/1400V	Jinzhou/Shuanghe
6	Resonance capacitor	1.2UF/500V	BeiJing
7	Reactor	?	Tianjin/Xiangyuanan (domestic brand)
8	Filter capacitor	300UF/230V	Zhengtai(domestic brand)
9	Main control board	?	?
10	Inverter control board	?	?
11	Touch Screen	?	Siemens
12	PLC	?	Siemens
13	Low-voltage electrical (Air switch,relay,contactor&other switches)	?	?(at user’s option)
14	Plate heat exchanger	SS304	Tianjin/Tianbanzhonghui
15	Water tank	Stainless steel	?

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