72 100-412-183 REV. 13
5.6 Converter Cooling
Converter performance and reliability can be adversely affected if the converter ceramics
are subjected to temperatures above 140º F (60º C). The converter front driver
temperature should not exceed 122º F (50º C).
To prolong converter life and maintain a high degree of system reliability, the converter
should be cooled with clean, dry, compressed air, particularly if your application calls for
continuous ultrasonic operation. Converter cooling is especially critical in 40 kHz
applications.
Use one of the following procedures to determine if a converter is operating close to the
maximum allowable temperature. Check converter temperature immediately after
substantial machine operation and without power applied to the horn.
• Press a pyrometer probe (or similar temperature measuring device) against the front driver of
the converter assembly. Wait for the probe to reach the temperature of the shell. If the
temperature is 120º F (49º C) or higher, the converter requires a cooling air stream
• If a temperature measuring device is unavailable, use your hand to feel the shell of the converter.
If the converter is hot to touch, the converter requires a cooling air stream
High duty cycles require additional cooling for the converter. System average power must
be limited to the specified continuous maximum. Higher peak power, up to the maximum
acceptable power limit, with an on time of up to 10 seconds may be obtained, if
appropriate off time ensures that, on average, the continuous duty maximum power is not
exceeded.
Table 5.20 Continuous Duty Max. Power & Full Power Duty Cycle
Configuration
Continuous Duty
Max. Power
Full Power Duty Cycle
20 kHz / 1250 W 800 W 10 s on 10 s off (50% Duty Cycle)
20 kHz / 2500 W 1600 W 10 s on 10 s off (50% Duty Cycle)
20 kHz / 4000 W 2000 W 5 s on 15 s off (25% Duty Cycle)
30 kHz / 750 W 300 W 2 s on 2 s off (50% Duty Cycle)
30 kHz / 1500 W 800 W 2 s on 2 s off (50% Duty Cycle)
40 kHz / 400 W 300 W 10 s on 10 s off (50% Duty Cycle)
40 kHz / 800 W 400 W 10 s on 10 s off (50% Duty Cycle)