Single Phase Connection

Up to 8 ELPA-SINE systems can be arranged in single phase parallel connection. Each electronic load is able to operate independently, so that systems can be reconfigured, expanded or broken up as needs dictate.

The current is actively shared between each load. The ammeter of the master unit shows the total current that is the sum of all ammeters, The voltmeters of the slaves will show SL1 and SL2. When operating in single-phase master slave operation, a number of test modes are not available. Please see the datasheet for more information.

The modular approach is useful for test houses and research labs who regularly test different sized power devices. Individual units can be used for the day to day testing of multiple small devices, then grouped together for larger projects.

Three Phase Connection

ELPA-SINE units with identical nominals can be configured in Δ or Y connections for 3 phase applications using the master/slave interface. The setting current value (single phase current value) will be sent to each slave unit automatically, the user does not have to set each unit. Equal parallel strings of up to 8 ELPA-SINE units can be configured per phase, up to 3 × 180kW.

Front Panel Memory

150-state memory allows quick initialisation and limit setting of the unit. Common test routines can be saved and executed at the touch of a button.

Sequencing Function

A sequencing function means that stored settings can be implemented against time, enabling the unit to carry out complex test routines without the need for a computer interface.

Every unit features constant current, constant voltage, constant power and constant resistance modes as standard. A linear constant current mode is also provided. The fast voltage transient response of the linear CC mode makes it especially suitable for non-sinusoidal AC voltage inputs such as step waveforms, square waveforms and any AC input voltage with a highly distorted waveform.

An adjustable frequency up to 440Hz is provided, as well as DC operation. Peak currents can be simulated with the crest factor mode. A leading or lagging power factor can be set with adjustments from unity to 0 lagging or leading. The desired wave can be recalled from the front panel or selected via an optional computer interface. 

Constant Current Mode

This is the most commonly used mode of operating when testing a voltage source. In this mode of operation, the load will sink a constant level of current as set by the user regardless of any voltage variations. A real time feedback loop ensures a stable current under any voltage variation of the DUT. This mode is recommended for load regulation testing, loop stability testing, battery discharge testing and any other form of voltage regulation loop testing.

Linear Constant Current Mode

In this mode the load current input depends on the current setting, regardless of the input voltage (i.e. the current setting remains unchanged). The load input current signal will follow the input voltage signal which is useful for step or square waveform devices. The automatic gain control circuit responds almost instantly to adjust for a sudden increase in input voltage. This fast voltage transient response makes is especially suitable for non-sinusoidal AC voltage inputs such as step waveforms, square waveforms and any AC input voltage with a highly distorted waveform.

Constant Resistance Mode

In this mode the ELPA-SINE will sink a current linearly proportional to the load input voltage in accordance with the programmed resistance setting. This mode is useful for discharge testing of battery systems used to power constant impedance loads, as the voltage decreases over time as the battery discharges resulting in reduced current sinking.

Constant Voltage Mode

The ELPA-SINE will attempt to sink enough current until the load input voltage reaches the programmed value. Most power sources are voltage controlled (i.e. they regulate the output voltage to a predefined voltage level). Such voltage supplies should not be tested using CV mode, as the supply voltage regulation loop will conflict with the load control loop.

Constant Power Mode

The ELPA-SINE will attempt to sink load power (load voltage × load current) in accordance with the programmed power. Constant power mode is useful for battery discharge testing as it simulates constant power drain on the battery, regardless of battery charge state.

Multiple inbuilt tests include UPS efficiency, PV inverter efficiency, UPS back-up time, battery discharge time, UPS transfer time, short circuit and fuse/breaker trip testing. Other interesting features of the ELPA-SINE include a turbo mode which can test currents up to double the maximum current of the unit up to 1 second, ideal for inrush current testing.

Rectifier Load Simulation

Each unit features a rectifier load mode. This allows users to test IEC test specification requirements for the UPS, IEC 62040-3 UPS Efficiency Measurement Non-Linear and IEC 61683.

Battery Discharge Function

The ELPA-SINE has three inbuilt battery discharge tests. The battery tests allow the user to set a voltage threshold to stop the discharge, avoiding accidental damage to the battery. Capacity in Ah, discharge time and voltage can all be read from the display.

Front Panel Control and Memory

Front panel control is provided as standard, which all the unit's test and operating modes can be implemented through. A four digit display simultaneously provides actual values taken by the load. Users can toggle between various measurements for: voltage, current, power, frequency, crest factor, power factor and harmonics.

Each ELPA-SINE features a front panel memory which can store 150 operation states or testing steps. Each state can store or recall the load status and level for the electronic load simultaneously. A sequencing function means that stored settings can be implemented against time, enabling the unit to carry out complex test routines without the need for a computer interface.

Analogue Interface 

The ELPA-SINE has an analogue programming input available on the rear panel of the load. The analogue programming input enables the load module to track and load according to an external 0-10V signal applied to the analogue terminal. The ELPA-SINE will attempt to load proportionally according to the signal and the load’s maximum current or power range.

Retrofitable Interface Cards (Optional)

A variety of interface options are available including RS-232, GPIB, USB and LAN. Interface cards can also be easily retro-fitted or even swapped in the field by the user, further expanding the ELPA-SINE's capability. This is possible by simply removing two screws, as highlighted.

A host of protection features guard the unit against over power, voltage, current and temperature.

Units can be treated to a laboratory rack or flight case integration. Having a programmable power system mounted into a flight case on castors is often advantageous, especially when several departments or test cells share the same equipment. Multiple power systems can be fitted into the same flight case.

Door hangers are fitted to flight cases for convenience. Existing ETPS systems can also be retrospectively integrated into new flight cases where requested.
 

If your test requirement is short term, we have a 3750W ELPA-SINE in our AC electronic load rental range.

Adjustable frequency is possible from 40-440Hz, making the units ideal for testing aerospace power sources. The ability to also sink DC sources helps to ensure that the ELPA-SINE is the perfect all-round lab kit.

Special UPS Waveform Applications

Many UPSs feature a modified sinewave which is designed to alternate load current on and off in order to simulate a sinewave. This is designed to create a waveform of 1ms on and 1ms off at 50Hz or 60Hz. This is typically a lower cost approach than producing a pure sinewave. The ELPA-SINE can be used to demand this type of waveform from the DUT. The plot shows a 110V/60Hz waveform in constant current mode set at 5A (Yellow CH1=Voltage; Blue CH2 = Current).

Current Protection Component Test

The ELPA-SINE provides a special fuse test function for the verification of current protection components (e.g. fuses, circuit breakers, PTC resettable fuses). This can test and verify protection devices using the rated current and power of the device under test. There are 2 types of fuse test, Trip (fuse) and Non-Trip (no fuse). Fuse test setting parameters include test current, test time and number of test repeats.

Inrush and Surge Current Testing

When applying AC power to a rectifier capacitor input circuit of a load, there is an inrush of current which decays. The ELPA-SINE’s inrush mode is unique in that the load does not need to sync up to the AC input voltage before applying current. A typical decaying inrush current when applying AC power to a rectifier capacitor input circuit of a load is shown below.