ZSAC Series

MANUFACTURER: Höcherl & Hackl
  • Voltage up to 440 V
  • Current up to 100 A
  • Power 400 W ... 21 kW
  • Frequency range up to 800 Hz
  • For single-phase and three-phase applications
  • Star and delta connection possible
  • Current and resistance mode
  • Dynamic loads
  • Programmable waveform
  • Phase shift combined with crest factor
  • Harmonics, phase control
  • SCPI programming with measurement function
  • Electronic protection
  • Isolated analog measurement outputs for voltage, current and power
  • Isolated analog control input

Operating Modes

The AC current loads of the ZSAC series feature constant current and resistance operating modes. In AC mode the current is sinusoidal. In resistance mode the height and waveform of the current depends on the input voltage.

Voltage Types

Depending on the type of voltage the devices can be switched between mains voltage and/or mains-synchronous voltage, AC voltage with variable frequency and DC voltage.


In current mode a low-distortion sinusoidal waveform is a permanently saved setting. In resistance mode the current depends on the waveform of the applied input voltage. Any waveform can be specified by programming and saved in the recallable waveform memory. Functions for harmonics, phase-controlled  currents and currents with adjustable crest factor are stored permanently. The phase angle adjustment is combined with the crest factor adjustment.


The inbuilt modulator enables two independently adjustable currents and times within the range from 100 μs ... 1 s. In AC mode the modulator serves to adjust the envelope curve of the AC current (amplitude modulation).

Remote Control

Most load functions can be controlled remotely via the standard Analog I/O Interface . The control inputs can be operated with TTL levels and 24 V from PLC controllers.

Analog Control Input

In the constant-current operating mode the current  can be set by  0 ... 3.5 V or 0 ... 7 V DC.

Analog Measurement Outputs

There are 0 ... 7 V analog measurement signals for voltage, current and power available.  The outputs are electrically isolated from the load input.


The units are air-cooled. To keep the operating noise low, the fans are controlled depending on temperature and current.


The ZS is a sturdy 19“ rack design and can also be used as a table-top device. From 5 height units there are retractable handles on the top of the device. Optional castors can be mounted on heavy devices. No separate installation kits are needed for 19“ rack installation.


All connections are at the rear side. The current connections are designed as touch-protected sockets for 4 or 6mm plugs.

Interfaces (Accessories)

The interface cards are removable and can be exchanged or expanded as required. The devices can be fitted with the following interfaces:

  • RS-232 + USB
  • GPIB + RS-232 + USB
  • System interface fiber optic
  • Ethernet-RS-232 converter

Factory Calibration Certificate

A free Factory Calibration Certificate (FCC) is supplied with the devices. The FCC meets the requirements according to DIN EN ISO 9000ff. This calibration certificate documents the traceability to national standards to illustrate the physical device in accordance with the international System of Units (SI). Within the warranty period we calibrate a second time for free.

--> Conditions for a second free calibration

The recommended calibration interval is 2 years.

Software Tools

The H&H homepage has a program library for Windows with a control tool and LabVIEW drivers.

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