Technical Tips

Motor Protection


May 2022

Overload Relay Code transition

Built-up motor starters with an O/L relay code for identification required a change as Sprecher+Schuh transitioned from 2nd generation CEP7-ED1/EE versions to the 3rd generation CEP7-1 versions.

CS7 Control Relay

September 2017

CEP7 Overload Relay Testing Procedures

What procedure can be used to test the phase loss or overload protection on a CEP7 overload relay?

CEP7-EEHF Overload Relay

January 2017

Theory and Operation of Overload Protection Used in CEP7(S) Overload Relays

How do the CEP7(S) solid-state electronic overload relays detect and react to overload conditions in a motor? How can I reset the overload? How quickly will the overload reset?

CEP7-EEHF Overload Relay

July 2016

CEP7-EE_F/G/H Large Amp Overload Replacement Module

The larger amp CEP7-EE_F/G/H overload relays for CA6 Contactors are designed in two pieces so the overload relay module can be replaced. There are two options for this replacement module.

CEP7 Overload Relays

March 2016

CEP7 Interchangeability of Single-Phase and Three-Phase Overload Relays

Can you interchange or swap out a single-phase CEP7S-EE__ overload relay with a three-phase CEP7-ED1__/CEP7-EE__ solid-state overload relay? If I wire or loop the single phase power source through the legs of the CEP7 Three-phase solid state relay, will this configuration protect the motor?

CEP7 Overload Relays

January 2016

What CEP7 Mounting Hardware Is Included in Box

Are bolts, mounting screws, washers and nuts supplied with CEP7-EEGF, CEP7-EEHF, CEP7-EEJF, CEP7-EEJG, CEP7-EEKG and CEP7-EELG overload relays? What are these hardware components used for?

CEP9 Overload Relays

June 2015

CEP9 Overload Relay Hardware Fault

How do I clear a CEP9 Overload Relay hardware fault (3 long, 7 short blink pattern)? A hardware fault can be cleared easily, but persistent problems may indicate further action is needed.

CEP9 Overload Relays

June 2015

CEP9 Overload Relay Device Modes and Dial Functions

What are the different device modes and the rotary dial functions of the CEP9 Electronic Overload Relay? The CEP9 Electronic Overload Relay has four device modes to validate configuration of the device and limit when a user can configure the overload relay, perform a firmware update, and issue commands.

CEP7 Overload Relays

May 2015

Heat Dissipation rates for CEP7 Overload Relays

What is the heat dissipation rate of the CEP7 overload relays? How does it compare to other types of overload relays? Sprecher + Schuh CEP7-ED_ and CEP7(S)-EE_ overload relays dissipate heat more efficiently than traditional thermal or eutectic alloy overload relays.

CEP9 Overload Relays

March 2015

SCCR information for CEP9 Overload Relays

The SCCR values for the CEP9-ESM Sensing modules can be found in the installation instructions included in the box. This is the manner in which UL requires the SCCRs to be specified.

CEP7 with CEP7-EPT Side Mount Module

February 2015

PTC Thermistor protection using CEP7-EPT Side Mount Module

What are the differences between the CEP7-EPT for thermistor protection and the old RT3/RT7 thermistor relay?

CEP7 Overload Relays

February 2015

The Test Button function on Overload Relays

What happens when the test button is depressed on the CEP7-ED1/EE overload relays? Will activating the test button show up as a trip on the overload relay? Do the CT7N and CT8 Overload Relays react in the same manner?

Phase Failure Protection

January 2015

Inside Story on Phase Failure Protection

One of the outstanding features of IEC type overload relays is protection of three phase motors in the event of a single phase condition; otherwise known as “open phase” or “phase failure “ in one of the motor leads.


CEP7 with Side Mount Modules

July 2012

How Ground Fault Works

Almost 80% of all short-circuit faults start as a low level arcing ground fault. Current sensing devices can stop a fault before it occurs.

Trip Class Selection

September 2011

Trip Class Selections

At what time is it considered a cold start? . . . or, a hot start? What is the necessary cool down time after a hot trip? Selecting the right trip class on an overload can make a difference.



Premium Efficiency Motor Protection

March 2011

Premium Efficiency Motor Protection

Ignoring the effects of increased inrush of premium efficiency motors could lead to nuisance tripping and lost production time.