Laser Manuals

1. Manufacturing Checkout Procedure

The Korad K15 power supply is designed for use with the K15, KWD and KHD series lasers. The function of this supply is to charge the storage capacitor bank to a selected voltage at a fast rate. For a complete description of the K15 supply and controls, see the “K15 Power Supply Instruction Manual”.

The purpose of this procedure is not to describe the K15 supply, but instead, provide an easy and safe method of testing and calibrating the supply. For this purpose, a special test fixture has been provided to test the supply.

2. Equipment Needed

  • K15 test fixture
  • Oscilloscope
  • 5 Kilojoule head with lamp and heat exchanger
  • DC hypot

3. Hookup

  • Connect the supply to the test fixture as shown in Figure 1.

4. Short Circuit Test

  • Before plugging in the 240 volt line plug, turn the power switch (on the supply) on.
  • Place an ohmmeter across the 240 volt line (across the switch terminals is convenient) and read approximately 12 ohms.
  • Place and ohmmeter from onee switch terminal to ground and read greater than 2 megahoms.
  • Repeat Step C for the other switch terminal.
  • Turn supply power switch off.
  • Plug 240 volt line connector into outlet.

5.0 - To Test The Interlock

Set the controls on the K15 test panel and the power supply controls as indicated and verify the following conditions.

A. Test Panel Controls

S1 S2 S3 S4 S5 S6
1 OFF OFF OFF OFF OFF

B. Supply Controls

Power Switch Kilovolt Dial Local-Remote Switch Auto Charge Dump
Light Button Light Button Light Button
ON 1.00 Local OFF OFF OFF

5.1 - To Test The Interlock

Repeat Step 5.0 with the controls as indicated.

A. K15 Test Panel Controls

S1 S2 S3 S4 S5 S6
1 OFF OFF OFF OFF OFF

B. Supply Controls

Power Switch Kilovolt Dial Local-Remote Switch Auto Charge Dump
Light Button Light Button Light Button
ON 1.00 Local OFF OFF OFF

To verify ground point and 120, 240 points:

Set the controls on supply as indicated, then rotate S2 from 1 through 3 and verify that the conditions indicated occur.

A. Power Supply Controls

Power Switch Kilovolt Dial Local-Remote Switch Auto Charge Dump
Light Button Light Button Light Button
ON 1.00 Local OFF OFF ON

B. K15 Test Panel Controls

S1 S2 S3 S4 S5 S6 Meter
(AC Volts)
Grd. Indicator
1 1 ON OFF OFF OFF 110-120 OFF
1 2 ON OFF OFF OFF 235-245 OFF
1 3 ON OFF OFF OFF 0 OFF

7.0 - To verify Test Points Out Of S1:

Set the power supply and test panel control as indicated in the tables. These controls will remain constant while verifying these output; but, note other controls will vary (see Step 7).

A. Supply Controls

Power Switch PPM Dial
ON 30

B. K15 Test Panel Controls

S1 S2 S3 S4 S5 S6
1 OFF ON OFF OFF OFF

7.1 - To verify Test Points Out Of S1:

Set the controls (variables) on the power supply and K15 test panel as indicated. Connect the oscilloscope to S1 and verify the outputs and other conditions as are indicated in Table 7.1.

Test Panel Controls Power Supply Controls

S1 S4 J1 DC Volt Kilovolt Dial Local-Remote Switch Auto Manual Dump
Light Button Light Button Light Button
1 OFF 32-36 1.00 Local OFF OFF ON
2 OFF 24-26 1.00 Local OFF OFF ON
3 OFF 14-16 1.00 Local OFF OFF ON
4 OFF 0(Ripple ok) 1.00 Local OFF OFF ON
4 OFF 8-10 1.00 Remote OFF OFF ON
5 ON 32-36 0.00 Local OFF OFF OFF
6 OFF 32-36 0.00 Local OFF OFF OFF
7 OFF 0(Ripple ok) 1.00 Local OFF OFF ON
7 OFF 24-26 1.00 Remote OFF OFF ON
8 OFF 25(Spikes) 1.00 Local ON PUSH ON OFF
9 OFF 0 1.00 Local OFF OFF ON PUSH
9 OFF 28-32 1.00 Local OFF ON PUSH OFF
10 OFF 34-38 1.00 Local OFF OFF ON PUSH
10 OFF 0 1.00 Local OFF ON PUSH OFF
11 OFF 0 1.00 Local OFF OFF ON PUSH
11 OFF 24-26 1.00 Local ON PUSH ON OFF
12 OFF 0(Ripple ok) 1.00 Local OFF OFF ON PUSH
12 OFF 0 1.00 Remote OFF OFF ON

8.0 - To Calibrate the Rep-Rate Circuit

A. Turn the supply off and remove the SCR control assembly card.

B. Solder a 10 meg ohm resistor (1/2 watt), R9, on the card.

C. Place the SCR control card back in the supply.

8.1 - To Calibrate the Rep-Rate Circuit

A. Set the test panel and supply controls as indicated:

S1 S2 S3 S4 S5 S6
8 OFF ON OFF OFF OFF

B. Power Supply Controls

S1 S2 S3 S4 S5 S6
1 OFF OFF OFF OFF OFF

C. Connect the scope to S1 on the test panel with time base set at 1.0 sec/cm, sensitivity at 10 v/cm, and sync. source to internal sync.

D. Turn the PPM dial completely counterclockwise.

E. Push the auto button and verify that spikes approximately 25V in amplitude occur.

F. Adjust R1 on the SCR control card until the spikes are 1.0 cm apart.

G. Turn the PPM dial clockwise until the spikes are 2 cm apart.

H. Loosen the set screws and remove the PPM dial, point the arrow to 30 PPM, and tighten the set screws.

I. Set the time base on the scope to 2 sec/cm.

J. Turn the PPM dial to 10 PPM and verify that the spikes are 3 cm apart.

Set the test panel and power supply controls as indicated:

A. Power Supply Controls

S1 S2 S3 S4 S5 S6
1 OFF ON ON OFF ON

B. Power Supply Controls

Power Switch Kilovolt Dial Local-Remote Switch Auto Manual Dump PPM Dial
Light Button Light Button Light Button
ON 1.00 Local OFF OFF ON 30

C. Set the scope sensitivity to 2 volts/cm, time base to 2 milliseconds/cm, and sync. on auto or internal.

D. Connect the scope to J3 on the test panel and verify an output similar to the one shown in Fig. 9.0(a), about 7V peak.

E. With the exception of the kilovolt dial, leave the control as in 9.0 Step (a) and (b). Turn the kilovolt dial to zero and verify that the waveform shown in Fig. 9.0(a) goes to zero and back to its original value as shown in Fig. 9.0(b).

Set the test panel and power supply controls as indicated. Push the manual button and verify that the supply charges to 1.00 kV and stop. If not, push dump button at 2.0 kV

A. Test Panel Controls

S1 S2 S3 S4 S5 S6
1 OFF OFF OFF OFF OFF

WARNING – At this point, very high voltage will be present in the supply when the manual button is depressed.

B. Supply Controls

Power Switch Kilovolt Dial Local-Remote Switch Auto Charge Dump
Light Button Light Button Light Button
ON 1.00 Local OFF OFF OFF

C. With the exception of the kilovolt dial, leave all controls as in 10.0 step (a) and (b). Turn the kilovolt dial to 3.00 kV push the manual button and verify that the supply charges to 3.00 kV and stop. If supply reads high or low, push the dump button, adjust R12 (on logic card) push the manual button to recharge the supply. Repeat this process until the meter reads 3.00 kV exactly.

D. Repeat Step (c) with the kilovolt dial set at 4.00 kV

E. Push dump button to discharge high voltage.

A. Connect a 5 Kilojoule head (with heat exchanger) to the lamp connector in the back of the test fixture.

B. Set the controls as in paragraph 10.0 step (d). Push the manual button and verify that the supply charges and fire lamp automatically at 4.00 kV

C. Make note of the shot counter reading.

D. With the control set as in Step (b), verify PPM dial is 10 PPM, push the automatic button and verify that supply charges and fire automatically every 6 seconds for 5 minutes.

E. Verify that the shot counter has advanced.

B. Supply Controls

Power Switch Kilovolt Dial Local-Remote Switch Auto Charge Dump
Light Button Light Button Light Button
ON 1.00 Local OFF OFF OFF

C. With the exception of the kilovolt dial, leave all controls as in 10.0 step (a) and (b). Turn the kilovolt dial to 3.00 kV push the manual button and verify that the supply charges to 3.00 kV and stop. If supply reads high or low, push the dump button, adjust R12 (on logic card) push the manual button to recharge the supply. Repeat this process until the meter reads 3.00 kV exactly.

D. Repeat Step (c) with the kilovolt dial set at 4.00 kV

E. Push dump button to discharge high voltage.

A. Turn the HV switch (S5 on the test panel OFF.
B. Turn the supply off and discharge the capacitor bank.
C. Disconnect the cable from J4 (H.V. out).
D. Connect a DC hypot across J4, or any point common to J4, and ground the hypot should be a negative supply with a positive ground.
E. Hook a variable resistor or a resistance substitution box (about 20 K to start) across K2 pin 2 and ground.
F. Set the kilovolt dial to 5.00 kV Make sure S5 on the test panel is OFF; all other controls on the test panel may be disregarded at this point.
G. Turn the supply’s power switch on.
H. Push the charge button. No H.V. Voltage will be present.
I. Turn the hypot on and increase the voltage to 5.3 kV Note that the meter on the supply will read off scale.
J. Increase the variable resistor across K2 pin 2 until the supply automatically dumps itself. QUICKLY TURN THE HYPOT VOLTAGE TO ZERO TO PREVENT EXCESSIVE CURRENT.
K. Measure the value of the resistance and replace it with a fixed resistor as close as possible with the same value.

A. Turn supply off. Use the discharge rod to discharge the capacitor bank.
B. Remove the supply from the test fixture.

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