Theory of Operation, Scr | Miller Electric TM-353E guide

SECTION 5 – THEORY OF OPERATION

	1	Input Terminal Board TE1
	Provides means for operation on
	different input voltages.

	2	Power Switch S1
			1-Phase

	Provide on/off control of unit.		Line
	3	Fan Motor FM	Input
			Power

Provides cooling of internal compo- nents.

4 Main Transformer T1

Supplies power to weld output cir- cuit, various control circuits, main control board PC1, and fan motor FM.

5 Control Board PC1

Controls weld output by changing the SCR gate pulses (conduction times) after comparing current feedback to selected amperage signal.

Also provides input connections for switches S3, S5, S6, and S7.

1

Input

Terminal

Board TE1

1φ

2

Power

Switch

S1

3

Fan

Motor

FM

1φ	4	AC	24
1φ	4		Background
	Main		Background
	Main		Power
	Transformer		Power
	Transformer		Source
	T1		Source
	T1
	115 VAC		DC
	14	23	DC
	14	23
	Circuit		Main
	Breaker		Rectifier
	CB1		SR1

15

115 VAC Duplex

Receptacle

RC2

	115 VAC
1φ , 10 VAC
Synchronization	SCR
Signal	Gating
	Signals

6Arc Control Switch S6 And Control R2

R2 selects short-circuit amperage when S6 is On, and High Frequen- cy control R13 is Off.

7Crater Time Switch S7 And Control R11

R11 selects crater time when S7 is on, and Amperage Control switch S5 is in Panel position.

8 Thermostat TP1

If T1 overheats, TP1 opens stop- ping all weld output.

9 Output (Contactor) Switch S3

Selects On or remote contactor control.

10 AC Balance Control R3

Controls changes to ac output square wave.

11Ammeter A1 And Voltmeter V1

Display weld amperage and volt- age while welding.

12Amperage Control Switch S5 And Adjustment Control R1

R1 selects weld output amperage when S5 is in Panel.

13Remote 14 Filter Board PC2/Remote 14 Receptacle RC1

PC2 protects unit from high fre- quency, and RC1 connects remote amperage and contactor controls to power source.

14 Circuit Breaker CB1

Protects 115 volts ac duplex recep- tacle RC2 from overload.

6

Arc Control

R2

7

Crater Time

Control

R11

9

Output

(Contactor) Switch S3

12

Amperage

Adjustment

Control R1

6

Arc Control

Switch

S6

7

Crater Time

Switch

S7

8

Thermostat

TP1

10

AC Balance

Control

R3

11♦

Ammeter

A1

12

Amperage

Control

Switch S5

5

Control

Board

PC1

16

Postflow

Timer

TD1

17

Gas

Valve

GS1

13

Remote 14

Filter Board

PC2

13

Remote

Amperage

Control

TM-353 Page 20

Syncrowave 250

Image 24

Miller Electric TM-353E manual Theory of Operation, Scr

Contents

SyncrowaveR Table of Contents Declaration of Conformity For European Community CE Products Page Safety Precautions for Servicing Symbol UsageMarks a special safety message Servicing Hazards EMF Information About Pacemakers + + + Definitions ISO/IEC Rating Label For CE Products Symbols And Definitions Some symbols are found only on CE products Installation SpecificationsVolt-Ampere Curves 220 230 260 380 415 460 Duty Cycle And Overheating 60% Duty Cycle At 200 AmperesOverheating Dimensions And Weights Selecting a LocationMovement Location And Airflow Be careful when placing or moving unit over uneven surfaces TippingWeld Output Terminals And Selecting Cable Sizes ARC Welding can cause Electromagnetic Interference Turn Off power before connecting to receptacle Remote 14 ReceptacleVolts AC Duplex Receptacle And Shielding Gas Connections Socket Electrical Service Guide All values calculated at 60% duty cycle Placing Jumper Links And Connecting Input Power Check label inside your unit- only one label is on unit Operation Controls Output Selector Switch Meters Crater Time Controls Spot Time ControlsApplication Setting Output Waveforms AC Balance ControlBalance Control AC Gtaw Amperage Adjustment Controls Output Contactor Control Switch Arc Controls Postflow Time ControlFor AC And DC Smaw Welding High Frequency Controls Preflow Time Control Optional Theory of Operation SCR HD1 Troubleshooting Troubleshooting Table Necessary parts Dition of contacts. Replace CR5 if necessary Contacts. Replace CR2 if necessary Troubleshooting Circuit Diagram For Welding Power Source See -1 for HD1 locationV24 D, E Waveforms For Section Gnd AC Output, 100 Amperes, 24 Volts AC Re- sistive Load Control Board PC1 Testing Information Use With Section Control Board PC1 Test Point Values Reference for gate pulse to SCR4 RC54 Not used Receptacle Pin Value Remote Board PC2 Testing Information Use With Section RC3 Meter Calibration Input Voltage Labels And Connections Maintenance Routine MaintenanceMonths Circuit Breaker CB1 Adjusting Spark Gaps Turn Off power before adjusting spark gapsFuses F1 And F2 Welding Processes Using HF Sources Of HF Radiation From Incorrect InstallationHigh Frequency HF Correct Installation Electrical Diagrams Model Serial Or Style Number Circuit Diagram Wiring Diagram SC-114 SC-120 SC-121 SC-124 SC-124 785-B SC-132 697-A SC-137 SC-135 SC-142 SC-148 SC-154 649-C SC-178 SC-179 303-A SC-181 109-E SC-188 161-A Syncrowave TM-353 TM-353 SD-188 162-A TM-353 SD-187 644 1 TM-353 SD-187 644 2 SA-121 SA-044 725-C TM-353 Description Parts List Main Assembly PLG51 114 BASE, Prior to KE727074 170 Panel, Front w/Components Panel, Front w/ Components Rectifier, Si Diode -1 Item Panel, Mtg Components -1 Item Control Panel, Lower Front 126 Capacitor ASSEMBLY, Eff w/JK537589 thru JK690986 C14 124 COIL, HF coupling Eff w/JK572898 thru KF959378 174 Optional Equipment Page Miller