Alternating current

Basic Insulation
Insulation between live parts, for basic protection against shock current. (VDE 0110-1:1997, section

Bath Tub Curve
Profile of the failure rate function of the main influencing factor (eg, time, cycles, etc.). This course can genernally be divided into three main areas.

Early failures: Here, the failure rate has a downward trend
. Random failures: In this area, the failure rate is constant; this area is called "service life".
Wear-out failure: where the failure rate increases as a result of wear and tear.
Bath Tub Curve

The burn-off is a loss of material at the contacts caused by electric arcs while switching.

Conductive part (relay contact), which is intended to connect or disconnect electrical circuits.

Contact arrangement
Combination of different contact types.

Contact spacing
Distance between the contact pieces of an open contact, as measured at the narrowest point.

Contact types
According to the different switching functions of contacts different contact types are distinguished. Distinction is also made between single and double contacts. The contacts directly moved by the drive system are active contacts, not actuated contacts are passive contacts.

Cycling Test
Test method for the reliability of contacts for switching dry circuit.

Direct current

Double or Reinforced Insulation
Insulation, which consists of base insulation and additional insulation.

Drive power
Power consumption of the coil in watts.

Drop-out Current
The dropout current is the maximum current at the relay coil, when the relay falls back into the rest position.

Drop-out Time
For normally open contacts: The time from switching off the coil excitation to the opening of the contact.
For normally closed contacts: The time from switching off the excitation coil until the moment of contact. (no bounce)
For change-over contacts: The time from switching off the coil excitation to the first contact with the opposite contact.

Drop-out Volltage
Maximum voltage at the relay coil, when the relay falls back into the rest position.

Electrical Endurance
Admissible number of operations with a survival probability of 95% for a given contact load under specified conditions (max. switching frequency, max. contact resistance, response or drop values, insulation values, etc.).

Fault Current
The largest current in the relay coil, in which no actuation of the contacts takes place.

Fire Safety Specifications
An assessment of the resistance against fire and possibly continued burning independently.

A collective term for all operations of foreign-layer destruction in a closed, static electrical contact.

Galvanic isolation
Secure, potential free insulation between conductive parts.

gold flash
Is a non-covering gold layer (layer thickness smaller 0.5μm) and serves as a so-called bearing protection. Because of being a porous gold layer the protective effect is controversial. Switching-wise the gold flash is irrelevant.

hard gold plating
Is a covering gold layer applied to the base contact material. It prevents contact corrosion and is used for switching small loads (dry circuits) where no or only very small arcs arise.

inductive load
For inductive loads, an indication of the life expectancy is different from application to application, because of increased inrush currents and the voltage spike when turning off. The different load types are summarized in several application categories, they correspond to the switching behavior of motors or transformers, for example.

Inrush Current (making capacity)
The highest current at the moment of switching on. Pay special attention to capacitors, when heating coils or lamps are within the circuit, especially since the inrush current can be substantially higher than the operating current. It can then amount to more than 10 times the value of the breaking current.

insulation resistance
Is the minimum resistance value at from each other isolated parts measured with an ohm meter or galvanometer at 500V DC. If the contacts are much better insulated against the coil or ground, this is noted accordingly in the relays table.

insulation values
Information on existing insulation between conductive parts.

Load Ranges
Dry circuits U < 80mV, I < 10mA
Low level circuits U < 300mV, I < 10mA
Minimum current circuits (in which "short arcs" occur)
Intermediate level circuits (loads in the intermediate region) U < 12 V, I < 300 mA
High level circuits (in which stable arcs are characteristic) U > 12V, I > 300mA
Low power contacts (High current contacts for low switching power)
Power contacts

Mounting Position
Specifies the required position of the relay in order to ensure proper relay function. All relays of ELESTA GmbH can be mounted in any position. There is no prescribed position.

Normally Open Contact [NO]
Relay contact which is closed in the operating position of the relay and open in the resting position.
Normally Open Contact [NO]

Operating temperature
The temperature of the relay during operation, after reaching the thermal equilibrium.

Operating Voltage
Is the voltage at which a relay is operated. The excitation voltage range indicates the range in which the operating voltage must be so that the relay is working correctly.

Output Contact
Contacts that are available to the customer for switching a load.

Output Side
Contacts on the relay for free use.

Persistent Current
Current which a relay contact can carry continuously under specified conditions without exceeding the permitted warming.

Response Delay
The response delay is a time that elapses from creating a response voltage until the actual response. Response delay, release delay, transient pulses, blinking mode and pulse shaping are often achieved by electronic timing elements that are connected upstream of the relay. Either the functions are combined with the relay in a component (time relay) or with the relay in a socket as a module.

Response Time
For normally open contacts: The time from switching the coil to the first contact.
For normally closed contacts: The time from switching the coil until the contact is opened.
For change-over contacts: The time from switching the coil to the first contact with the contact to be closed.

Response Voltage
Minimum value of the excitation voltage, which brings a relay to operate. The specification of response voltage is usually based on 20°C.

Temperature increase of a device during operation due to the power loss occurring in the device, eg the coil and the contacts of the relay.

In monostable relays it means that the anchor does not return to the rest position after the excitation of the coil. The reason for this may be either too low return force or high remanence in the iron circuit. This effect can be counteracted by applying a release sheet or release pin.