The ITS Team will be performing maintenance on Confluence beginning at 6:00 pm Tuesday, October 8. During this time the service may go offline. It should be available again by 8:00 pm. Please refrain from editing pages during this time to avoid losing your work.
General
Ensure that all power supplies are OFF, and that all controls are set at zero before proceeding.
The Test Data Sheet lists the cathode voltage required for maximum power at discrete frequencies. The cathode voltage required for other frequencies may be obtained by interpolation.
Refer to the absolute rating listed in the SPECIFICATIONS (in appendix) and the test data supplied with each EIO.
Set the maximum cathode current trip to the value posted on the EIO. The maximum body current trip may be set to the value specified in the absolute ratings; however, the body current is generally set a few mA above the value listed in the Test Data Sheet.
Initialization Checklist
It is recommended that the following checklist be covered before applying any voltages:
- Connect the collector to the power supply positive.
- Connect the body (normally ground) to the power supply positive.
- Ensure the heater, cathode, and anode leads are adequately insulated; connect the leads to their respective power supplies.
- Ensure coolant flow is adequate.
- Ensure, by the use of trips, adjustment stops, etc. that the absolute ratings will not be exceeded. (Refer to Maximum Ratings in appendix.)
- Connect the O/P flange and the I/P flange (where applicable) to suitable RF loads.
- Ensure personnel will not be subject to exposure from the microwave fields.
- Ensure personnel cannot come into contact with any high voltage.
CONFIGURATION 1 - Refer to Figure 3
Connect the EIO to the power supplies as shown in Figure 3. Configuration 1 is similar to the circuit used with the CPI EIK Power Supply, Model VPW2827. Protect the EIO as discussed above.
Switch the heater supply ON. When the minimum specified heater delay has elapsed, the beam power supply may be turned ON. Set the beam voltage to the value specified for the desired frequency of operation on the Test Data Sheet, an exact setting is not requited.
NOTE:
The anode voltage is referenced to the cathode. When the anode voltage is switched OFF, the anode-to-body (ground) voltage equals the beam voltage. As the anode voltage is increased, the anode-to-body voltage decreases.
Switch the anode power supply ON and increase the anode voltage until the beam current specified on the Test Data Sheet is obtained.
CAUTION:
DO NOT ALL THE ANODE TO BECOME POSITIVE WITH RESPECT TO THE BODY. THE ANODE VOLTAGE SHOULD EXCEED -50 VOLTS WITH RESPECT TO BODY WHEN THE EIO IS OPERATING.
Adjust the tuner until the EIO oscillates at the desired frequency. With the beam voltage set correctly, the EIO should be operating at the peak power for the mode; i.e., at the maximum power consistent with the beam current specified on the Test Data Sheet for the operating frequency.
The beam voltage may be optimized to obtain the maximum possible RF power output. Varying the beam voltage produces a corresponding change in the frequency due to electronic tuning.
Adjust the beam voltage to obtain the maximum possible power.
Retune the EIO to obtain maximum possible power at the required frequency.
The power output may be reduced by lower the anode voltage.
CAUTION:
DO NOT, UNDER ANY CIRCUMSTANCES, EXCEED THE MAXIMUM BEAM CURRENT OR BODY CURRENT SPECIFIED IN THE OPERATING INSTRUCTIONS FOR THE INDIVIDUAL EIO
THE ABSOLUTE RATINGS MUST BE ADHERED TO
Special attention should be paid to maximum current, and to the polarity and value of the anode potential.
Turn-Off Procedure
- Switch the anode power supply OFF.
- Switch the beam power supply OFF.
- Switch the heater power supply OFF.
- Switch the mains power supply OFF.
NOTE:
The EIO power supply, VPW2827, may be shut-down fast by switching the beam power supply OFF; the anode power supply will automatically switch OFF.
NOTE:
Opening an interlock will have the same result.
CONFIGURATION 2 - Refer to Figure 4
Connect the EIO to the power supplies as shown in Figure 4. Protect the EIO as discussed above.
Set the anode potentiometer to approximately center position.
Switch the beam power supply ON and set the voltage to the value specified on the Test Data Sheet for the desired frequency of operation; an exact setting is not required.
Set the anode voltage to provide the beam current specified on the Test Data Sheet.
Adjust the tuner until the EIO oscillates at the desired frequency. With the beam voltage set correctly, the EIO should be operating at peak power for the mode; i.e., at the maximum power consistent with the beam current specified in the Test Data for the operating frequency.
The beam voltage may be optimized to obtain the maximum possible RF power output. Varying the beam voltage produces a corresponding change in frequency due to electronic tuning.
Adjusting the beam voltage to obtain the maximum possible power.
Retune the EIO to obtain maximum possible power at the required frequency.
Repeat the beam voltage and the tuner adjustments until maximum power has been obtained at the operating frequency.
The power output may be reduced by lower the anode voltage with respect to the beam voltage.
NOTE:
With this configuration, the beam current will change when the beam voltage is changed.
CAUTION:
DO NOT, UNDER ANY CIRCUMSTANCES, EXCEED THE MAXIMUM BEAM CURRENT SPECIFIED IN THE OPERATING INSTRUCTIONS FOR THE INDIVIDUAL EIO
THE ABSOLUTE RATINGS MUST BE ADHERED TO
Special attention should be paid to maximum cathode current, and to the polarity and value of the anode potential.
Turn-Off Procedure
Switch the beam power supply OFF.
Switch the heater power supply OFF.
Switch the mains power supply OFF.