China Medium Voltage Frequency Inverter - High Reliability from Top Suppliers and Factory for 20-Year Fault-Free Operation

Model Meaning

1. The dimensions and weight are for reference only; the exact dimensions and weight shall be as specified in the technical agreement.
2. For standard series units, the input voltage is identical to the output voltage.
3. The overall height does not include the height of the cooling fan; an additional 300 mm to 600 mm should be added for the fan height.
4. The above overall dimensions and weight refer to the combined total of the control cabinet, power unit cabinet, and transformer cabinet excluding the line-frequency bypass cabinet.
5. The minimum clearance requirements are as follows: at least 1500 mm from the front of the equipment to the wall, at least 1000 mm from the rear, at least 800 mm from either side, and at least 1000 mm from the top of the equipment to the ceiling.
6. Standard overload capacity is 120% for 1 minute, allowed once every 10 minutes. Optional overload capacities of 125%, 150%, or 200% are available to meet different application requirements.
7. The applicable motor power rating may vary depending on the motor type and construction, and is provided for reference only.

Model Selection

Primary Circuit Diagram

Harmonic-Free Solution

The secondary winding of the phase-shifting transformer employs an extended delta connection, altering the phase angle of each secondary winding per phase.

• This mitigates the impact of harmonics generated by the unit on the power grid.
• Taking two units connected in series as an example for analysis: the phase-shift angle o = 60°/2 = 30°
• The current is referred to the primary input side and expanded into a Fourier series:

The 5th, 7th, and 11th harmonic components have phase angles differing by 180°, and through phase-shifting rectification technology, these harmonics cancel each other out.

Take the input phase-shifting transformer of a 10kv variable frequency drive (VFD) as an example. Its primary winding is rated at 10kv, while the secondary side consists of 24 three-phase windings, each with an output voltage of 690v. Every winding adopts an extended delta connection and has a phase shift angle difference of 7.5°. This configuration can effectively eliminate harmonics below the 47th order, which means that 48-pulse rectification is capable of suppressing harmonics lower than the 47th order (calculated by the formula 6n-1, where n refers to the number of units per phase).

Industry Applications

Main Features

• Low-voltage ride-through (LVRT)
• Auto-restart after power loss (within 20 seconds)
• Power cell bypass function
• Flying-start (spin-start) capability
• Synchronous switching function
• Redundant control power supply (optional)
• Redundant power unit design (N+1, optional)
• Redundant cooling fans (optional)
• Other functions customizable per customer requirements
• Dedicated control function module for mills
• Magnetizing inrush current suppression cabinet
• One-drive-one manual bypass cabinet
• One-drive-two manual bypass cabinet
• One-drive-one automatic bypass cabinet
• One-drive-two automatic bypass cabinet
• One-drive-one synchronous switching cabinet
• Output reactor cabinet
• Isolation cabinet