Centrifuge and power controlling apparatus including a voltage switching unit
A centrifuge includes a rotor which accommodates a sample, a motor which rotationally drives the rotor and a chiller which cools a rotor chamber, and is provided with a transformer which has a plurality of secondary side taps, converts an AC voltage which is input from a primary side to a plurality of voltages, and outputs, and a voltage switching unit which is connected to the plurality of secondary side taps of the transformer, selects any one of outputs of the secondary side taps, and outputs to the chiller. The microcomputer controls the voltage switching unit corresponding to the power supply frequency which is determined using the output of the zero-crossing detection circuit, and supplies the desired driving voltage to the chiller.
1. A centrifuge comprising:
a rotor configured to accommodate a sample;
a motor configured to rotationally drive the rotor;
a bowl configured to define a rotor chamber which accommodates the rotor;
a chiller configured to maintain temperature of the rotor chamber to a desired temperature by cooling the bowl;
a control unit configured to control a rotation of the motor and an operation of the chiller;
a transformer which includes a plurality of secondary side taps and is configured to transform an AC voltage which is input from a primary side to a plurality of voltages;
a voltage switching unit configured to be connected to the plurality of secondary side taps, select any one of the plurality of secondary side taps, and output an output of the selected secondary side tap; and
a frequency determination unit configured to determine a frequency of the AC voltage,
wherein the control unit controls the voltage switching unit so as to select one of the plurality of secondary side taps which corresponds to the frequency determined by the frequency determination unit.
2. The centrifuge according to claim 1 , wherein the chiller is configured to be able to operate according to a plurality of power supply frequencies, and of which operating voltage is different for each power supply frequency.
3. The centrifuge according to claim 2 , wherein the AC voltage supplied to the motor and the control unit is supplied from any one of the secondary transformer taps without using the voltage switching unit.
4. The centrifuge according to claim 1 , wherein the transformer is a step-down transformer which has the plurality of secondary side taps on secondary winding and a plurality of taps on primary winding.
5. The centrifuge according to claim 1 , wherein
the frequency determination unit includes:
a zero-crossing detection unit which is connected to any one of the plurality of secondary side taps of the transformer, and is configured to detect timing in which an output voltage of the transformer crosses a potential of 0 V; and
a calculation unit configured to calculate the frequency by measuring the interval of the zero-crossing signal which is output from the zero-crossing detection unit.
6. The centrifuge according to claim 5 , wherein
the control unit includes a microcomputer, and
the calculation unit is implemented by the microcomputer.
7. The centrifuge according to claim 1 , wherein
the voltage switching unit is connected to the chiller through a semiconductor relay which controls turning on and off of power to the chiller, and
the control unit controls on and off states of the semiconductor relay.
8. The centrifuge according to claim 7 , wherein the semiconductor relay is a solid state relay with a zero-crossing detection unit built-in.
9. A power controlling apparatus for driving a device, comprising:
a transformer which includes a plurality of secondary side taps and is configured to transform an AC voltage which is input from a primary side to a plurality of voltages;
a voltage switching unit configured to be connected to the plurality of secondary side taps, select any one of the plurality of secondary side taps, and output an output of the selected secondary side tap to the device;
a frequency determination unit configured to determine a frequency of the AC voltage; and
a control unit configured to control the voltage switching unit so as to select one of the plurality of secondary side taps which corresponds to the frequency determined by the frequency determination unit.
10. The power controlling apparatus according to claim 9 , wherein the transformer is a step-down transformer which has the plurality of secondary side taps on secondary winding and a plurality of taps on primary winding.
11. The power controlling apparatus according to claim 9 , wherein
the frequency determination unit includes:
a zero-crossing detection unit which is connected to any one of the plurality of secondary side taps of the transformer, and is configured to detect timing in which an output voltage of the transformer crosses a potential of 0 V; and
a calculation unit configured to calculate the frequency by measuring the interval of the zero-crossing signal which is output from the zero-crossing detection unit.