An inverter transforms direct current (DC) into alternating current (AC), in this case, at a constant frequency.

Input source (DC)

The DC input can come from solar panels, rectifiers – chargers, batteries, DC bars, etc. The voltage is usually variable because the power sources operate in highly volatile situations. For that reason, the Jemainverter is designed to accept a wide margin of variation in input voltage while maintaining the desired output parameters.

Transfer by-pass

The inverters work on-line and usually include a static transfer by-pass to an auxiliary support grid for emergencies and a manual by-pass for maintenance work.

Device design

The device has excellent dynamic behaviour with IGBT transistors. It’s controlled by a microprocessor that governs the unit in response to different keywords and signals it receives and informs the user of its status. If it includes a by-pass, it synchronises with the auxiliary grid. Control functions:

• History: last 250 alarms with time and date
• Automatic control: programmable start up and shut down
• Diagnostics: visualise and transmit the status of the device
• Measurements:
• V_ef and I_ef of all phases
  • Active, apparent and reactive power
  • Internal system temperatures
  • yield, power and frequency factor
  • Test: automatic, local/remote, periodic and programmable
  • Digital settings: parameters adjustable by keyboard
  • Configurable: basic system functions can be defined
  • Tips for using the keyboard

General features of the device 

• Digitally synthesised perfect sine wave output
• High frequency stability and output voltage
• High performance, simplicity and reliability
• Excellent behaviour with non-linear unbalanced loads
• Multiprocessor digital control, PWM modulation
• Interface using a display, keyboard, LEDs and serial communication
• Built in galvanic isolation transformer
• Can optionally operate in parallel with other units

• Input: 24 / 48 / 110 / 125 / 220 Vdc – Voltage margin depending on design
• Output: From 1 to 1300 kVA – Single-phase 220 VAC ± 1 % – Three-phase 220 / 380 / 400 VAC ± 1 % – Voltage adjustment ± 5 % Vn – Frequency 50 / 60 / 400 Hz ± 0.1% – allowable cos 0.6 capacitive / 0.4 inductive – Harmonic greater 3 % – Max. distor. THD global linear load < 3 % – non-linear load < 5 % – Dynamic response ± 5 % – Response time 30 ms – Crest factor 3 – Yield 80 – 93 %, depending on power
• Options Transfer by-pass, without cut-off– LBP line stabiliser transformer – Redundant – Operation in parallel with other units –Anti-earthquake Class 1E – Output distribution board – Manoeuvre board – Adaptation to diverse regulations (MIL, UL …)
• Design: Self-supporting metal cabinet – IP20 to IP54 Protection – Colour RAL 7032 (standard)

All the features above can be modified on demand.

• Input: Three-phase 220 / 380 / 400 VAC + 15 % – 10% – Frequency 50 / 60 Hz ± 5% – power factor up to 0.9
• Output: From 5 to 1300 kVA – Frequency 50 / 60 / 400 Hz ± 0.1 % – Single-phase 220 VAC ± 1 % – Three-phase 220 / 380 / 400 VAC ± 1 % – Voltage adjustment ± 5 % Vn – allowable cos 0.6 capacitive / 0.4 inductive – Harmonic greater 3 % – Max distor.THD global linear load < 3 % – non-linear load < 5 % – Dynamic response ± 5 % – Response time 30 ms – Crest factor 3 – Yield 80 – 93 %, depending on power
• Options: Pb or NiCd batteries – 6 or 12 pulses – Anti-harmonics filter – LBP line stabiliser transformer – 28 VDC / 160 a 1000 A Auxiliary source – Redundant – Operation in parallel with other units – Class 1E Anti-earthquake – Output distribution board – Manoeuvre board– Adaptation to diverse regulations (MIL, UL, …)
• Design: Self-supporting metal cabinet – IP20 to IP54 Protection – Colour RAL 7032 (standard)

All the features above can be modified on demand.

Operating principles

A rectifier transforms alternating current (AC) into direct current (DC). Its normal function is charging batteries and keeping them in optimum conditions while, at the same time, providing DC power for other loads. Consequently, it’s essential that the unit takes into account what kind of batteries it’s feeding (Pb or NiCd) when operating.

It works automatically and continuously evaluates the status and temperature of the batteries and other system parameters in order to guarantee stable voltage and low ripple.

It can incorporate load disconnection manoeuvres for the end of autonomy, thermal-magnetic distribution, fault localisation, grid analysers, etc.

Battery charge limits and levels

With sealed Pb batteries, only two current levels are used (float and charge), while three are used for open Pb and NiCd batteries: float, fast charge and deep charge.

• Float: for maintaining the battery when already charged depending on the temperature.
• Fast charge: Done in the shortest time possible to restore capacity lost by the battery during discharge; at limited current and final voltage of stabilised charge.
• Deep charge or deformation: Periodic manual operation to equalise the battery elements; at limited current and final voltage of stabilised charge. Done in a vacuum.

Shift from float to fast charge and vice-versa:

• Automatically: when current above a specified value is suddenly absorbed, adjustable. And the opposite, after the absorbed current drops.
• Manually (optional): pushing a local / remote button.

General features of the device 

• Complete, automatic wave rectifier
• High power factor at input, up to 0.9
• High output voltage stability, rippled up to 0.1% RMS
• High performance, simplicity and reliability
• Can be used in parallel with other units