TRASA3 Knowledge Base

Electrical Component Parameter Reference

An open technical reference for electrical component types, their applications, and selection parameters.

This material is also available in PL and RU.

Device description

Thermal Overload Relay

Electromechanical or thermal-bimetal motor protection device responding to sustained overcurrent.

A thermal overload relay protects a motor against prolonged overload by using a current-dependent thermal element.

Typical parameters include current-setting range, trip class, time-current characteristic, ambient-temperature compensation, and phase-loss sensitivity.

The relay normally operates with a contactor and, when tripped, opens the control circuit to stop the motor.

Selection considers motor rated current, starting class, ambient conditions, reset method, and contactor compatibility.

Components in this subcategory

Thermal and bimetal overload relays for motor protection.

Available parameters

Thermal Overload Relay

129 parameters
Dimensions4
Widthmm

External horizontal dimension of the product between its outermost lateral points.

Heightmm

External vertical dimension of the product from its lowest to its highest point.

Depthmm

External distance between the foremost and rearmost surfaces of the product.

Net Weightkg

Mass of the product itself, excluding transport packaging, additional accessories, and external equipment.

Materials and Finish7
Material

Primary material from which the product is manufactured.

Material Grade

Grade, alloy, class, or technical designation of the product's primary material.

Color

Primary visually perceived colour of the product's external surface.

RAL Color

Designation of the product's primary surface colour according to the RAL colour system.

Surface Finish

Type of final surface finish of the product determining its appearance and service properties.

Surface Treatment

Technological surface treatment applied to modify its protective, mechanical, or decorative properties.

Coating Type

Type of protective, functional, or decorative coating applied to the surface.

Mounting and Installation23
Mounting Type

Installation arrangement permitted by the product design, such as wall-mounted, flush-mounted, floor-mounted, or another specified mounting type.

Mounting Method

Method used to mechanically secure the product to a support, surface, or load-bearing structure.

Mounting Surface

Type of surface or supporting base to which the product may be fixed.

Orientation

Permissible spatial orientation of the component during installation and operation.

Number of Mounting Holes

Number of holes provided in the product for mechanical fixing.

Mounting Hole Diametermm

Diameter of the hole provided for a fixing element used when mounting the product.

Horizontal Mounting Hole Spacingmm

Distance between the centres of mounting holes in the horizontal direction.

Vertical Mounting Hole Spacingmm

Distance between the centres of mounting holes in the vertical direction.

Mounting Pattern Widthmm

Horizontal dimension of the mounting pattern between the outermost fixing points of the product.

Mounting Pattern Heightmm

Vertical dimension of the mounting pattern between the outermost fixing points of the product.

Mounting Screw Size

Size designation of the screw, bolt, or other threaded fastener used for mounting the product.

Mounting Thread

Designation of the thread provided in the product's mounting holes or fixing elements.

Mounting Tightening TorqueNm

Tightening torque recommended or permitted for fasteners during product installation.

Fasteners Included

Indicates whether the required fasteners are included with the product.

DIN Rail Mounting Supported

Indicates whether the design provides for mounting equipment on a DIN rail.

Direct Device Mounting Supported

Indicates whether equipment may be mounted directly to the mounting surface without an intermediate DIN rail.

Required Top Installation Clearancemm

Minimum free space required above the product for installation, cooling, or servicing.

Required Bottom Installation Clearancemm

Minimum free space required below the product for installation, cooling, or servicing.

Required Left Installation Clearancemm

Minimum free space required to the left of the product for installation or servicing.

Required Right Installation Clearancemm

Minimum free space required to the right of the product for installation or servicing.

Required Front Installation Clearancemm

Minimum free space required in front of the product for installation and normal operation.

Required Rear Installation Clearancemm

Minimum free space required behind the product for installation and normal operation.

Maximum Mounting Tilt Angle°

Maximum angle permitted by the manufacturer by which the product may deviate from the specified reference orientation during installation.

Electrical Parameters34
Supply Current Type

Type of electrical current for which the product's main supply circuit is intended.

Rated VoltageV

Voltage value assigned to the product by the manufacturer for specified application conditions and characteristics.

Rated Operational VoltageV

Operating-circuit voltage with reference to which the product's performance characteristics are specified.

Minimum Operating VoltageV

Minimum voltage at which the manufacturer guarantees the intended operating mode of the product.

Maximum Operating VoltageV

Maximum voltage at which continuous operation of the product is permitted under the conditions declared by the manufacturer.

Rated FrequencyHz

AC frequency assigned to the product for normal operating conditions.

Minimum FrequencyHz

Lower limit of the electrical network or signal frequency at which product operation is permitted.

Maximum FrequencyHz

Upper limit of the electrical network or signal frequency at which product operation is permitted.

Rated CurrentA

Current assigned to the product by the manufacturer for the declared operating and thermal conditions.

Continuous Service CurrentA

Current that the product can carry continuously under the manufacturer's declared conditions without exceeding permissible temperature rise.

Rated Insulation VoltageV

Voltage with reference to which the product's insulation clearances and dielectric properties are specified.

Rated Impulse Withstand VoltagekV

Peak value of an impulse voltage of specified waveform that the product insulation must withstand without breakdown.

Dielectric Test VoltageV

Test voltage applied to verify the dielectric strength of the product insulation.

Minimum Insulation ResistanceMΩ

Minimum permissible insulation resistance between the specified electrically separated parts.

Overvoltage Category

Category characterizing the expected level of impulse overvoltages at the product's point of use.

Pollution Degree

Degree of pollution of the surrounding microenvironment considered when selecting insulation distances and product characteristics.

Electrical Protection Class

Class of protection against electric shock determined by the product design and protective connection method.

Supported Motor Types

Motor technologies and motor types that the product is designed to control, start, protect or drive.

Supported Motor Phase Configurations

Electrical phase configurations of motors supported by the product.

Minimum Supported Motor Rated CurrentA

Minimum motor rated current supported by the product.

Maximum Supported Motor Rated CurrentA

Maximum motor rated current supported by the product.

Main Terminal Connection Type

Conductor connection technology used specifically for the main power terminals of the switching device.

Minimum Main Terminal Conductor Cross-Sectionmm²

Minimum conductor cross-section accepted by the main power terminal.

Maximum Main Terminal Conductor Cross-Sectionmm²

Maximum conductor cross-section accepted by the main power terminal.

Main Terminal Tightening TorqueNm

Manufacturer-declared tightening torque specifically for screw, bolt or clamp-type main power terminals.

Control Terminal Connection Type

Conductor connection technology used specifically for the control-circuit terminals.

Minimum Control Terminal Conductor Cross-Sectionmm²

Minimum conductor cross-section accepted by the control-circuit terminal.

Maximum Control Terminal Conductor Cross-Sectionmm²

Maximum conductor cross-section accepted by the control-circuit terminal.

Control Terminal Tightening TorqueNm

Manufacturer-declared tightening torque specifically for a screw-type control-circuit terminal.

Relay Contact Maximum Switching VoltageV

Maximum manufacturer-declared voltage that may be switched by the relay-output contacts.

Relay Contact Maximum Switching CurrentA

Maximum manufacturer-declared current that may be switched by the relay-output contacts.

Relay Contact Maximum Switching PowerW

Maximum manufacturer-declared active power that may be switched by the relay-output contacts.

Mechanical Endurancecycles

Declared number of mechanical operating cycles that the product can perform without electrical switching load.

Electrical Endurancecycles

Declared number of electrical load-switching cycles under the conditions specified by the manufacturer.

Protection and Safety19
IP Rating

Degree of enclosure protection against access to hazardous parts and ingress of solid objects and water, designated by the IP code.

Front-Side IP Rating

IP degree of protection provided by the accessible front side of the product after its intended installation.

IK Rating

Class of enclosure resistance to external mechanical impacts designated by the IK code.

Ingress Protection Certified

Indicates whether the declared ingress protection of the enclosure has been verified by certification or testing.

Protection Against Direct Contact

Method or level of protection of the user against direct contact with hazardous live parts.

Minimum Overload Current SettingA

Minimum adjustable overload current setting.

Maximum Overload Current SettingA

Maximum adjustable overload current setting.

Overload Current Setting StepA

Smallest selectable increment of the overload current setting.

Supported Overload Trip Classes

Standardized overload-relay trip classes supported or selectable by the product.

Minimum Trip Time at 7.2 × Overload Settings

Minimum declared trip time from the applicable initial condition at 7.2 times the overload current setting.

Maximum Trip Time at 7.2 × Overload Settings

Maximum declared trip time from the applicable initial condition at 7.2 times the overload current setting.

Overload Temperature Compensation Supported

Indicates that overload tripping characteristics are compensated for ambient temperature.

Minimum Overload Compensation Temperature°C

Minimum ambient temperature within the declared overload temperature-compensation range.

Maximum Overload Compensation Temperature°C

Maximum ambient temperature within the declared overload temperature-compensation range.

Motor Phase-Loss Sensitivity Supported

Indicates that the motor overload protection characteristic is specifically sensitive to single-phasing or phase-loss conditions through motor-current imbalance or an equivalent protection principle.

Protection Functions

Set of protection functions integrated into the product or provided by it in its normal intended configuration.

Supported Reset Modes

Reset or restart modes supported after the condition that caused a trip, protection action, alarm or safety stop has been cleared.

Test Button Present

Indicates whether the product has a local TEST button for the specified functional check of the device.

Trip Indicator Present

Indicates whether a local mechanical or electronic indicator shows that the circuit breaker has tripped protectively.

Environmental Conditions19
Minimum Operating Temperature°C

Minimum ambient temperature at which normal operation of the product is permitted.

Maximum Operating Temperature°C

Maximum ambient temperature at which normal operation of the product is permitted.

Minimum Storage Temperature°C

Minimum ambient temperature permitted during storage of the product while not in operation.

Maximum Storage Temperature°C

Maximum ambient temperature permitted during storage of the product while not in operation.

Minimum Relative Humidity%

Minimum relative air humidity permitted for the declared operating or test condition.

Maximum Relative Humidity%

Maximum relative air humidity permitted for the declared operating or test condition.

Relative Humidity Reference Temperature°C

Temperature at which the corresponding relative humidity value is specified or standardized.

Humidity Condition

Nature of the humidity conditions for which product operation or resistance is declared.

Non-Condensing Humidity

Indicates whether the permissible humidity value applies only to non-condensing conditions.

Maximum Installation Altitudem

Maximum altitude above sea level at which the product may be installed without exceeding the declared conditions.

Altitude Derating Required

Indicates whether the permissible product load must be reduced as installation altitude increases.

Altitude Derating Startm

Altitude above sea level above which the permissible product load must be reduced.

Vibration Resistant

Indicates whether the product's resistance to vibration has been verified under the declared conditions.

Minimum Vibration FrequencyHz

Lower limit of vibration frequency applied or permitted in the relevant test.

Maximum Vibration FrequencyHz

Upper limit of vibration frequency applied or permitted in the relevant test.

Vibration Accelerationm/s²

Amplitude or test-method-specified acceleration of vibration applied during product testing.

Mechanical Shock Resistant

Indicates whether the product's resistance to short-duration mechanical shocks has been verified.

Shock Accelerationm/s²

Maximum acceleration generated during mechanical shock testing of the product.

Shock Durationms

Duration of an individual mechanical shock pulse during product testing.

Included Equipment5
Auxiliary Contacts Supported

Indicates whether the product supports installation or connection of specified auxiliary contacts.

Auxiliary Contacts Included

Indicates whether one or more auxiliary contacts are included in the standard product configuration.

Normally Open Auxiliary Contact Count

Number of normally open (NO) auxiliary contacts installed in or supplied with the product.

Normally Closed Auxiliary Contact Count

Number of normally closed (NC) auxiliary contacts installed in or supplied with the product.

Changeover Auxiliary Contact Count

Number of changeover auxiliary contacts installed in or supplied with the product.

Standards and Compliance18
Primary Product Standard

Primary normative document or standard according to which the manufacturer classifies or assesses the product.

Additional Standards

Additional normative documents and standards declared by the manufacturer as applicable to the product.

Declaration of Conformity Available

Indicates whether an official declaration of conformity is available for the product.

Certificate Available

Indicates whether a certificate relating to the declared certification or conformity of the product is available.

CE Marked

Indicates whether the CE marking is applied to the product where applicable.

UKCA Marked

Indicates whether the UKCA marking is applied to the product where applicable.

EAC Marked

Indicates whether the EAC marking is applied to the product where applicable.

UL Listed

Indicates whether the product has a declared UL Listed certification or recognition status.

UL Recognized

Indicates whether the product has a declared UL Recognized certification or recognition status.

cULus Marked

Indicates whether the cULus mark is applied to the product where applicable.

IEC 60529 Compliant

Indicates whether the manufacturer declares product compliance with IEC 60529.

IEC 62262 Compliant

Indicates whether the manufacturer declares product compliance with IEC 62262.

IEC 60068 Tested

Indicates whether the product has been tested according to applicable methods of the IEC 60068 series.

RoHS Compliant

Indicates whether product compliance with applicable RoHS restrictions on hazardous substances has been declared.

REACH Compliant

Indicates whether the manufacturer declares compliance of the product with applicable REACH Regulation requirements.

WEEE Applicable

Indicates whether the product falls within the scope of WEEE requirements for waste electrical and electronic equipment.

IEC 60947-4-1 Compliant

Compliance with IEC 60947-4-1 requirements applicable to electromechanical contactors and motor-starters.

UL 60947-4-1 Compliant

Compliance with UL 60947-4-1 requirements applicable to contactors and motor-starters.