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Frequently Asked Questions

Find answers to your questions about TELE's organization, technology, and the Smart Factory.


How does the Voltage monitoring, three-phase work?

TELE offers voltage monitoring for complex multi-wire networks. This means that also networks with strongly non-symmetric loads and with disruptive influences, TELE monitoring relays carry out their reliable work. And they do so not only in Europe for the usual three-wire networks with or without zero cable 3(N)~ 400/230V, but also for global application in different voltage levels and multi-wir systems that are switched in other ways.

A major application area for three-phase voltage monitoring is building technology. Here, it is important to monitor the height of the individual phase voltage in order to initiate emergency lighting with undervoltage and to protect consumption points from overvoltage. With the TELE devices specialised in these fields, the deviation of the phase voltage is set directly and the device switches off when at least one of the phases leaves the permissible range. The ENYA and KAPPA series are designed for contact-safe installation in the installation distributor. To simplify the wiring, most devices take their auxiliary energy from the current circuit measured.

The GAMMA industry series focuses on the monitoring of the supply voltage of motor. Damage can be prevented by switching off the motor in the event of network errors. Over- and undervoltage as well as asymmetrics errors are also reliably detected in complex industry networks. TELE monitoring relays are immune to voltage retroactivity of three-phase loads.

How does the Voltage monitoring, mono-Phase work?

To ensure the operation of 1-phase consumption points, it is worthwhile monitoring the power network. If the power supply is interrupted, this can lead to malfunctions in the system. TELE monitoring relays detect unreliable statuses at an early stage and initiate the measures envisaged for this. However, overvoltage can result from a network error that represents a major risk for entire system parts. This, however, can largely be prevented with robust monitoring technology.

The application areas of one-phase voltage monitoring range from battery monitoring to the control of the inverter in solar systems with insufficient energy production or the recognition of a drop in voltage with overlong cables. One-phase voltages over a wide area can be monitored with the devices of the GAMMA and TREND series. The compact automatic voltage controllers of the ENYA and KAPPA series are specialised in the undervoltage monitoring for typically standardised supply voltages.

How does the current monitoring work?

TELE current sentinels protect machines and loads through the monitoring of the system for overvoltage or undervoltage. During monitoring of the overvoltage, switched off or failed consumption points are recognised and the TELE current sentinel issues an alarm message.

For universal use, the WatchDogs of the GAMMA series have 3 measurement ranges. Specifically for use in combination with current or signal converters, the inputs are designed with a nominal value of 5A, 1A or 20mA respectively.

The integrated start-up bridging avoids false activation resulting from the increased start-up current of a Motor.

How does the fill-level-monitoring work?

In the conductive fill-level monitoring, the moistening of the probe rods is analysed. The recording of the conductivity using alternating current of a few milli-amperes with 12 V voltage is used. The use of alternating current effectively suppresses galvanic effects such as those that can occur with a static direct voltage.

The advantage of this method is that the probe rods only have to meet the condition of electrically isolated installation and the conductivity of the probe themselves. The probes can therefore be simply adapted to the requirements of the environment. Whether it is particularly robust in animal breeding, agriculture or wastewater preparation, or also resistant against high temperatures such as those that can arise with sterilisation through hot steam.

To avoid the connected pumps being frequently switched on and off too frequently, a switching hysteresis can be defined by the distance of the max & min probe. However, this can also be completely deactivated, if the device is to be used as an overfill protection or dry-run protection for a pump.

Do you have custom solutions for my particular industry?

Yes! TELE works with its partners and customers to develop monitoring and control solutions for special sets of problems. Using our modular development platform, we can handle even industry-specific problems quickly, with standardization, and at the required scale. Are you struggling with issues related to plant safety, network stability, or energy efficiency and do you need a solution that is network-capable with the ability to visualize or save data? Challenge us!

Why has TELE discontinued the production of mains-decoupling relays?

For our fact finding concerning this product please refer to the following:

The ONF3 uses current monitoring to detect the switching on of loads in a household circuit. Monitoring voltage is 200mV DC.
This works well with resistive loads or Edison lamps. 
But with introduction of more and more electronic control and start circuits, reliable load detection and automatic restart become more and more impossible. Those circuits simply do not drain current at a low voltage level of 200mV.

Increasing the sensing voltage to detect switched-on loads, would be a possible technical solution or work around of above situation. But the increased sensing voltage (let’s say 50V DC) would spoil the effect to keep the circuits  volt- and-field free when not in use. But to guarantee field free power lines is the key feature of such a device!

Else we recognise more and more remote controlled or network connected devices, all of them operating with high frequency pulsed signals. Would it make sense in such an environment to have the powerlines volt-free only to reduce the impact of electromagnetic fields?

For this reason we decided to fade out production of this item. We do not plan for a new type with comparable functionality.

Will TELE monitoring devices be damaged by overcurrent in case of starting a motor?


For the current monitors series GAMMA the maximum overload is indicated app. 20% above nominal current. In case of a starting a motor there will be an inrush current eventually higher than this.

The TELE current monitoring relays are designed to work properly under real life conditions. In respect to high inrush currents of motors and bulb lamps the short time inrush current for GAMMA current monitoring G2I…. G2C…… and G2J…. types
is much higher than the stated continuous over current.

The values found below are supposed to be an inrush current applied to a cold unit (room temperature) Please let the unit cool down without any load prior to every test cycle for about 5 minutes


Values for G2I…and G2C…

10A-range: 50A for 5sec 75A for 2sec 100A<1sec
5A-range: 20A for 5sec 30A for 2sec 100A<180msec
1A- & 2A-range:  10A for 5sec 15A for 2sec  50A<180msec
100mA-range 800mA for 5sec 1,5A for 2sec  6A<180msec

20mA range: no separate inrush current specified.
Signal transmitter usually limit the current below the max. permissible continuous current of 250mA


Three-Phase-Current monitoring G2JM

3 inputs 5A- each: 25A for 2sec 15A for 5sec


Load Monitors: G2B…G4B…

Input range 12A:

 32A for 10sec 45A for 5sec  70A for 2sec  100A < 1sec
Input range 16A:
40A for 10sec 60A for 5sec  90A for 2sec  130A < 1sec

Generel infos

How much are your transport costs?

Package transport costs are as follows:

  • up to 5 kg – 9,90 €
  • from 5 to 15 kg – 13,70 €
  • from 15 to 31 kg – 19,40 €

What are your opening hours?

Cash sales: Mon.-Thurs. 7:30 a.m. to 4:30 p.m., Fri.: 7:30 a.m. to 1:00 p.m.

Where do I pick up the products?

Products may be picked up at Slamastrasse 37, 1230 Vienna during normal business hours.


Your smart factory

What does Your Smart Factory mean?

TELE is Your Smart Factory. It is a technology company with a tremendous amount of technical know-how and people who enjoy their work. TELE develops and manufactures control and monitoring solutions for the industrial and energy sectors. But TELE also has a truly novel organizational structure. Without traditional hierarchies. Without bosses. But plenty of personal responsibility. And collaboration. Learn more about Your Smart Factory here

Why do you have a new organizational structure without traditional hierarchies?

Because rigid hierarchies are inflexible and slow and because our success in a networked world depends on us being agile and nimble. But this works only when decision-making paths are short, ideally when each employee independently moves his or her own projects forward. This makes every person an entrepreneur. Initiative, curiosity, fun, responsibility, cooperation, and esteem are expected of each individual.

Innovation + sustainability = profitability

Where does TELE manufacture its monitoring and control solution?

We develop and manufacture our solutions and components at our Smart Factory at our Vienna headquarters.

We are a startup. How can we collaborate with TELE?

Simply contact us if you have developed a unique solution that makes the world better and you are ready for the next step but need a competent partner who will support you with know-how, technology, and resources.

Why do you collaborate with startups?

The “Smart Factory” develops clever technologies. When there is something that we do not yet know ourselves, we learn through cooperation with others. That is why we seek out and promote young innovators in exciting projects and give them access to know-how and resources.

Christian Esterlus
Christian Esterlus Sales

May I help you?

Do you have any questions about our solutions or about the company of the future? We've prepared a few answers here.

Vorarlberger Allee 38
1230 Wien, Austria

Tel.: +43 1 614 74–0
Fax: +43 1 614 74–100

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