Contents:
A high voltage unit (HV) is a special device that transforms power of a standard electrical network into high voltage required for operation of certain components of CNC machines, such as laser emitters or plasma cutting systems. This equipment is critically important for operation of high-tech CNC installations and performs several functions at once: generating and stabilizing high electric power, supplying energy to working elements and protecting from overloads.

Principles of working
Main components
- Transformer: is needed in order to “transform” standard mains voltage into needed for operation of machine components. Depending on type of equipment and technology, converted voltage can range from several thousand to tens of thousands of volts.
- Rectifier and filters: Initially, alternating current flows in the network, but constant current is needed to operate the machine. The rectifier and filters are engaged in conversion of second from the first.
- Voltage regulator and current protection: The machine must have a stable electricity at any moment of its operation, otherwise it may affect not only the result, but also damage important components of the machine. The regulator saves you from all this.
- Protection and cooling system: Like any other one, this one also tends to overheat, so the unit is equipped with an active and passive cooling system (fans and radiators).

The part of HV in operation of various types of CNC machines
Laser CNC machines
How does the laser appear in CNC machines? It’s all about HV. It is he who supplies electric power to the laser tube, in which a mixture of gases (usually a mixture of CO2, nitrogen and helium) is ionized to produce the beam itself. To do this, the unit must provide a stable electricity in the range from 5 to 25 kV, depending on the laser power.

Why HV is needed?
Its critically important to have stable electric power in a laser system for having high laser beam quality. Unstable power can lead to loss of quality or even damage to laser tube.
Plasma CNC machines
In order for the plasma arc to be constant, the power at its electrodes must be high (3-10 kV), this will make the arc stable and continuous during the entire processing.
Why HV is needed?
Stable plasma arc means good cutting quality. Too low voltage can lead to a rupture of the arc, and excessively high power can lead to rapid wear of the electrodes and destruction of the burner.
Electromechanical CNC machines
In electroerosion machines or electroplating systems, the HV is used to generate an electrostatic field or discharge.
Why HV is needed?
High electric power is necessary to create a stable electric field or discharge that affects the material or forms a processing circuit. Unstable stress or its absence can make the machining process impossible or lead to defects on the surface of the workpiece.
How to choose a HV for a CNC machine?
Voltage and power matching
Before choosing a high voltage unit, it is important to determine the required output voltage and power, which must match the characteristics of the target equipment. For example, a 100W laser may require a high-electricity unit with an output of 10 kV and a current of 30 mA.
Output voltage type
Depending on the type of equipment, the unit can generate DC, AC, or pulse voltage. Laser installations usually operate at constant power, while plasma installations can use a pulsed mode.
Built-in protection
Built-in protections (against overheating, short circuit, and voltage surges) are necessary for the safe operation of high-electricity equipment. When choosing a unit, make sure that it has all the necessary security features.
Cooling system
During intensive work, the high-voltage unit gets very hot, so it is important that it is equipped with an efficient cooling system. It can be a fan, radiator, or liquid cooling one, depending on the requirements.
Manufacturer and build quality
Give preference to trusted manufacturers such as Siemens, Delta, ABB, which have a long history of producing high-quality high-electricity devices. This will ensure durability and stable work of the unit.

Recommendations for operation of HV
Installation and connection
Install the HV according to manufacturer’s recommendations. Improper connection or use of unsuitable cables may cause device to fail or malfunction.
Parameter checking and calibration
Before starting operation, it is necessary to check all parameters and calibrate the system. This is especially important for new installations or after replacing HV.
Temperature and cooling level control
Regularly check the condition of the cooling system, liquid level (if liquid cooling is used) and cleanliness of ventilation openings.
Conclusion
The HV is a key element that ensures operation of many processes in CNC machines, especially in laser and plasma systems. The correct choice, installation and operation of a HV will avoid many problems and ensure stable and efficient operation of equipment.