C. Ground Leakage Detected:
A continuous tone accompanied by the
illumination of the ground leakage light. The voltage and wattage displays
will hold their last value. The milliamps display will go blank. (See below
“Ground Leakage”)
D. Power On Restart:
Nine short bursts in groups of three each with
each output display showing decimal points. This alarm activates to alert
the operator to the fact that auto-restart will occur at the end of a mains
power failure. The alarm will clear itself.
E. Overheating Detected:
A continuous tone accompanied by flashing
displays. This alarm indicates the heatsink, located at the rear of the unit,
has exceeded safe operating temperatures. Momentarily turning off the
power supply will clear the alarm. (See Service)
F. Mains Overload:
A continuous tone accompanied by flashing displays.
This alarm is indistinguishable from the “Overheating detected” alarm. It
indicates an internal fault or a temporary surge in the mains supply.
Momentarily turning off the power supply will clear the alarm. (See Service)
Unit Will Not Start:
This power supply is equipped with a load sensing
interlock which is designed to inhibit the generation of high voltage whenever
an open connection is detected at the output.
Open Connection:
An open connection is defined as a break in the path
in which electricity normally flows. This could be caused by any of the follow-
ing conditions:
1.
A broken electrode within the electrophoretic chamber.
2.
A broken wire within the connecting cord (either positive or negative).
3.
Insufficient buffer levels within the electrophoretic chamber.
4.
Loose connectors in any electrical connection going to or coming from the
power supply or chamber.
5.
Electrochemical energy stored within the chamber. (See below, “Unit Will
Not Restart ”)
Unit Will Not Restart:
Certain types of electrophoretic techniques will,
over a period of time, store energy within the electrophoretic chamber. This
charge may inhibit the normal function of the load sensing interlock when
attempting to restart an experiment which has been temporarily interrupted.
To overcome this effect depress and hold the D.C. Output On key until the
power supply reaches its proper operating voltage. Upon releasing the D.C.
On key the power supply should remain engaged. If it will not remain
engaged refer to the section entitled “Unit Will Not Start”.
No Displays Light:
This power supply is equipped with 2 circuit breakers
located at the rear of the instrument. If either circuit breaker is activated the
power supply will not turn on. When activated, the circuit breakers expose a
white stem.
12
6.
Gently press the D.C. Output
On key (24). The Red D.C.
Output On light (23) should illu-
minate and the D.C. output as
indicated by the three displays
(3, 5, 7) should rapidly
increase until the operating volt-
age limit is reached. At this
point the Yellow At Limit light
(volts) (2) should be the only “at
limit” light illuminated.
On
Off
DC Output
LIMITS
Electrophoretic chambers are generally designed for a relatively specific purpose.
For example, horizontal chambers use agarose gels to separate DNA or RNA frag-
ments while a DNA Sequencing chamber is almost always used to separate DNA
in a denaturing polyacrylamide gel. In each case, the voltage, milliamp and
wattage requirements are well– defined within a reasonable range of values. In
cases such as these, the user can safely assume that the manufacturer has designed
the chamber to withstand the voltage and heat energy necessary to perform the
electrophoretic separation when standard protocols are followed.
Some types of electrophoretic chambers are specifically designed to be multipur-
pose devices. For example, a vertical slab gel chamber could be used for anything
from DNA Sequencing to Isoelectric Focusing depending on the gel type and buffer
system used. Choosing safe operating limits for a chamber of this type requires a
24, 23,
3, 5,
7, 2
5
NOTE:
The power supply output may be adjusted while operating. If you turn any
of the three adjustment knobs while the D.C. Output On light is illuminated, the
power supply will automatically switch to the Set Display Mode. Each display will
show the set operating limit while in this mode and new limits may be set. One sec-
ond after releasing the adjustment knob the power supply will revert to the Display
Actual Mode.
Operation in Constant Current:
The method used to set the power supply
in constant current is the same as the method used for constant voltage. The only
difference involves the selection of an operating limit for current which, as the out-
put increases, is attained before the operating limits for voltage or watts.
Operation in Constant Watts:
The method used to set the power supply in
constant watts is the same as the method used for constant voltage. The only dif-
ference involves the selection of an operating limit for watts which, as the output
increases, is attained before the operating limits for voltage or current.
THERMO EC HIGH VOLTAGE POWER SUPPLIES
THERMO EC HIGH VOLTAGE POWER SUPPLIES
