Eaton S801+Soft Starter Complete Guide

Eaton S801+Soft Starter: The Ideal Choice for Intelligent Motor Control

In modern industry, the starting process of three-phase asynchronous motors directly affects the stability of the power grid, mechanical life, and production efficiency. Direct starting can generate a surge of up to 6-8 times the rated current, leading to voltage drops and excessive mechanical stress. The S801+soft starter launched by Eaton adopts an advanced six SCR fully controlled bridge topology, which smoothly increases the motor terminal voltage by continuously adjusting the thyristor conduction angle, thereby controlling the starting torque and current. After the motor reaches the rated speed, the thyristor is short circuited through an internal bypass contactor to achieve efficient operation. This article is based on the official user manual and provides a comprehensive analysis of the technical characteristics, installation requirements, functional configuration, parameter settings, and fault handling of S801+soft starter.

Product Overview and Technical Standards

1.1 Function and purpose

S801+soft starter is an electronic, self-contained motor soft starter device suitable for panel or cabinet installation. It controls the voltage applied to the motor to achieve smooth mechanical and electrical starting, suitable for centrifugal pumps, fans, compressors, conveyors, and other occasions that require limiting starting current and reducing mechanical shock. This series of products offers multiple current levels, covering application requirements from 37 A to 1000 A (taking S801+N37 to S801+V10 as an example).

1.2 Compliance with standards

S801+meets the following international and regional standards:

UL 508 (Industrial Control Equipment)

CSA C22.2 No.14-1995

IEC 60947-4-2 (Low voltage switchgear and control gear - AC semiconductor motor controllers and starters)

CCC GB14048 (China Compulsory Certification for Products)

1.3 Main Technical Highlights

Six SCR topology: one pair of anti parallel thyristors per phase to achieve full wave voltage regulation.

Built in bypass contactor: The motor automatically bypasses after reaching the rated speed, reducing conduction losses.

Control Interface Module (CIM): intuitive knob and DIP switch configuration, parameters can be set without software.

Multiple start/stop modes: voltage ramp, current limit, jump start, soft stop.

Comprehensive motor protection: thermal overload, locked rotor, phase loss, phase sequence, overcurrent, undervoltage, etc.

Wide environmental adaptability: Operating temperature range of -40 ° C to+50 ° C, no need to reduce capacity within an altitude of 2000 meters.

Technical data and specifications

2.1 Environmental conditions

Parameter specifications

Operating temperature -40 ° C to+50 ° C

Storage temperature -50 ° C to+70 ° C

Altitude ≤ 2000 meters, with a capacity reduction of 0.5% every 330 meters after exceeding it

Humidity ≤ 95% without condensation

Pollution level 3 (IEC 60947-1)

Anti impact 15 g (in any direction)

Anti vibration operation/non operation: 3 g

2.2 Mechanical dimensions and weight

S801+offers multiple frame sizes (N, R, T, U, V) to accommodate different current levels. For example:

S801+N37: Width 67.6mm, height 187.2mm, depth 163.9mm, weight 2.6kg.

S801+V10: width 280.6 mm, height 420.8 mm, depth 187.8 mm, weight 41.4 kg.

2.3 Short circuit rating

Different frameworks are suitable for circuits with different short-circuit capacities and should be used in conjunction with appropriate fuses or circuit breakers. Typical values:

N Framework: 10 kA/600 V (with JHFD type fuse)

R framework: 10 kA/600 V (RK5 or JHFD/HKD type fuse/circuit breaker)

T. U-frame: 18-30 kA/600 V

V-frame: 42 kA/600 V

Installation and wiring

3.1 Mechanical Installation

Check the equipment for any transportation damage before installation.

Drill holes on the panel according to the dimension diagram in the manual, and use bolts of the specified specifications (such as 1/4 inch bolts for V-frame with a torque of 50 lb in).

Ensure that the installation surface is flat and all fixing points use hardware.

For heavier V-frames (up to 103 lb), suitable lifting equipment should be used.

3.2 Main circuit wiring

S801+adopts an online connection method, where the power lines are connected to L1, L2, and L3, and the motor lines are connected to T1, T2, and T3. Wiring precautions:

Short circuit protection devices (fuses or circuit breakers) must be installed on the line side.

When wiring, follow local electrical regulations and use copper wires (75 ° C).

For T, U, and V frames, the standard supply does not include wiring terminals and requires separate ordering of wiring harness kits (such as EML22, EML28, etc.).

The wiring torque depends on the wire size, for example, a 4 AWG wire with a torque of 45 lb in.

3.3 Control circuit wiring

The control circuit is connected through a 12 bit terminal block and an RJ12 interface (connected to CIM).

Power supply: The terminal+/- needs to be connected to a 24 Vdc control power supply (SELV). The power capacity needs to meet the requirements of steady-state 25 W and surge 240 W (continuous for 150 ms).

Input signal:

Terminal P: Operation allowed (24 Vdc must be continuously applied to start)

Terminal 1: Start command (triggered by level or edge, depending on DIP switch S1 setting)

Terminal 2: Jog (Jog)

Terminal 3: Overload protection disabled during startup (for debugging only)

Terminal 4: Reset

Auxiliary contacts: Terminals 13, 14, 95, 96, 98 provide relay outputs that can be used to indicate operating status or faults. Contact capacity: 3 A/120 Vac or 24 Vdc, maximum 10 A (resistive).

3.4 DIP switch settings

The detection method for selecting the start command of S1 switch:

OFF (factory default): Level triggered, that is, when terminal 1 maintains 24 Vdc, as long as the allowable conditions are met and there are no faults, the motor will start.

ON: Edge trigger, which means that terminal 1 must have a rising edge from 0 to 24 Vdc to start, and the rising edge must be reapplied after fault reset.

The S2 switch has no function in S801+.

Working principle and start/stop mode

S801+uses six thyristors internally to form a three-phase fully controlled bridge. During the starting process, by gradually increasing the conduction angle of the thyristor, the motor terminal voltage is smoothly increased from the preset initial torque value to the full voltage. When the motor approaches synchronous speed, the internal bypass contactor closes, the thyristor is short circuited, and the motor is directly powered by the power supply, thereby reducing thyristor losses.

4.1 Voltage ramp starting

This is the most commonly used mode. The voltage starts from the initial torque value and linearly increases to full voltage within the set soft start time. If the motor reaches synchronous speed ahead of schedule, the bypass contactor will close early, and the soft start time may be shortened.

4.2 Current limit starting

In this mode, the soft starter maintains a constant current upper limit (determined by the initial torque setting) instead of a voltage ramp. Suitable for situations where strict limitation of grid surge current is required. Attention: It is not recommended to use it for variable torque loads such as fans and pumps.

4.3 Kick Start

For loads with high static friction, a short-term high torque pulse can be applied during the initial start-up period. The sudden jump torque and duration can be set separately through the potentiometer on CIM.

4.4 Soft Stop

When stopping, the voltage gradually decreases within the set soft stop time, causing the motor to slowly stop to avoid water hammer effect or mechanical shock. Attention: Soft stop is not braking and will not shorten the downtime.

Parameter setting and protection function

5.1 Control Interface Module (CIM)

CIM is installed on the S801+front panel and provides the following configuration components:

FLA potentiometer: Set the motor's full load current (range: 32% to 100% of the frame's rated current).

Starting time potentiometer: 0.5-180 seconds.

Initial torque potentiometer: 1% to 85%.

Jump torque/time potentiometer.

Soft stop time potentiometer: 0-60 seconds.

Overload level DIP switch: optional levels 5-30, default 20.

Fault indicator light: The S.S. Trip LED flashes to indicate a fault code.

5.2 Protection parameters and fault codes

S801+has multiple built-in protection functions that can be enabled/disabled through CIM:

Overload protection (thermal memory model)

Stall: When starting, the motor has not reached synchronous speed and the current is greater than 2 × FLA.

Jam: Current>3 × FLA during operation.

Lack of phase/phase sequence/phase imbalance

SCR short circuit/open circuit detection

Bypass contactor malfunction

Control power undervoltage

When a malfunction occurs, the S.S. Trip LED lights up, and the flashing code can be read by pressing and holding the reset button. For example:

Description of code faults, possible causes, and countermeasures

11. Excessive thermal overload load, low FLA setting, and frequent starting.

14 phase sequence error. The incoming phase sequence does not match the set value. Swap two phases.

The 22 phase loss fuse is blown and the circuit is disconnected.

32 SCR short circuit SCR breakdown, measure phase to phase resistance to confirm.

The control voltage is low, and the 24V power supply capacity is insufficient or the line voltage drop is too large.

5.3 Thermal Overload Model

S801+uses a thermal memory model to simulate motor temperature rise and can provide overload protection levels 5, 10, 20, and 30 as specified in IEC 60947-4-2. The heat accumulation value is stored in non-volatile memory and will not be lost when powered off. After each overload trip, the reset suppression time gradually increases (3 minutes for the first time, 6 minutes for the second time, and 9 minutes for the third time) to allow the motor to cool down.

Typical wiring and application precautions

6.1 Three wire button control

The manual provides wiring diagrams for three wire and two wire button systems. Typical three wire wiring: the stop button (normally closed) is connected in series with the allowable circuit (terminal P), and the start button (normally open) is connected to terminal 1. Auxiliary contacts can be used to indicate operational status.

6.2 Selection of 24 Vdc Power Supply

S801+requires control of power capacity: steady-state 25 W, surge 240 W for 150 ms. It is recommended to use Eaton PSG series power supplies, such as PSG240E (240 W) or PSG480E (480 W).

6.3 Coordination with bypass contactor

If an isolation switch or contactor needs to be installed on the load side, it must be operated after the soft starter has stopped, otherwise it may damage the SCR or cause false faults.

6.4 Power factor compensation capacitor

The power factor compensation capacitor must be connected to the power supply side of the soft starter and maintain a minimum cable distance of 10 feet from the soft starter. It is strictly prohibited to connect capacitors to the load side, otherwise it will affect overload detection.

Debugging and troubleshooting

7.1 Pre commissioning checklist

The main circuit wiring is correct and the phase sequence is correct.

Control the power supply to 24 Vdc and connect it correctly, with a voltage of ≥ 18 Vdc.

Allow terminal P to have a 24 Vdc signal.

CIM parameter setting: FLA equals the motor nameplate value; The starting time and initial torque are adjusted according to the load; Set the overload level to an appropriate value (usually 20).

If there is a phase sequence fault during the first power on, switch the incoming lines L1 and L2.

7.2 Common Fault Handling

The device does not respond to the start command: check if the allowed terminal P has 24V; if the LED is green; If it is red, read the fault code and handle it; If it is edge triggered mode, the start signal needs to be reapplied.

Starting time too long or too short: Adjust the initial torque and starting time potentiometer. If the static friction force of the load is high, a sudden jump start can be activated.

Sudden tripping during operation: Record fault codes and check for overload, phase loss, or overheating. If it is an overload, check if the load has increased or if the FLA setting is too low.

The bypass contactor cannot be closed: check if the control power supply capacity is sufficient (the voltage drop during surge should not be lower than 17V); Check if the contactor coil is normal; If the soft starter fails to close after multiple attempts, it will switch to SCR operation mode and may eventually overheat and trip.

7.3 Fault code reading

In the fault state, press and hold the reset button on CIM (or apply 24V to terminal 4), and observe the number of flashes of S.S. Trip LED. For example, flashing 3 times, stopping and then flashing 2 times indicates fault code 32. After releasing the button, determine the cause of the malfunction according to Appendix E of the code query manual.

Accessories and Options

S801+offers multiple options to meet different installation needs:

Wiring kit: EML22~EML33, suitable for different cable specifications and quantities.

Panel installation kit: EMA69A~EMA69D, including 3-10 feet of cable, used for remote installation of CIM on cabinet doors.

Installation board/anti vibration board: EMM13xx, EMM14xx, used to simplify installation or enhance anti vibration.

IP20 protective cover: SS-IP20-xx, used to improve terminal protection level.

Fan kit: EMM18, designed to enhance heat dissipation (for high-power applications).

Motor and special application considerations

9.1 Motor type

S801+is suitable for standard squirrel cage motors and can also be used for special motors such as star delta, partial winding, dual voltage, multi speed, etc., but correct wiring is required. For star delta motors, they must be connected in a delta operation mode, and soft starters cannot be connected between internal windings.

9.2 High inertia load

For high inertia loads such as fans and centrifuges, it is necessary to increase the starting time and initial torque appropriately, and use jump starting if necessary. Pay attention to checking the number of starts per hour to avoid exceeding the SCR thermal capacity.

9.3 Frequent Jogging

In Jog mode, the bypass contactor will not close and the motor will be powered entirely by SCR. Frequent tapping can cause SCR to heat up, and it should be ensured that the cumulative on-time per hour does not exceed the allowable value.