Resolver · Multi-speed resolver

Multi-speed resolver (2, 3, 4 speed) repair and alignment

Multi-speed resolver is a Resolver, 4 pole or more encoder with one electrical cycle per pole pair. We test it, repair or replace it and align it to the rotor. Found on: Servo motors with as many pole pairs as the resolver speed. Star Automations is an independent multi-brand repair company and is not an OEM service centre.

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25+years of servo repair, since 2000
3,000+customers across India
100+servo brands covered by our universal servo motor test equipment
5sites: Puducherry, Chennai, Bengaluru, Hyderabad, Delhi
Same dayemergency repair option*

*Where the fault and parts allow. Every repaired unit returns with a printed test report.

Repair turnaround you can plan around

Send a photo of the nameplate first. We confirm whether the motor is repairable, and the quote, the same working day.

Emergency: same day

For a line-down motor, where the fault and parts allow. WhatsApp us before you send it so the bench is kept free.

Urgent: 3 working days

Repair, encoder alignment and test, counted from the day the motor reaches the bench and the quote is approved.

Standard: 7 working days

Full repair, encoder alignment, run test under load and a printed test report.

Free repairability check from a nameplate photo
Printed test report with every motor
Written warranty, terms stated on every quotation
Pickup can be arranged; parts that must be imported are quoted with their own timeline

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01Facts

Multi-speed resolver at a glance

Device	Multi-speed resolver
Brand family	Resolver
Type and format	Resolver, 4 pole or more
Counts	one electrical cycle per pole pair
Found on	Servo motors with as many pole pairs as the resolver speed
Connector	Per motor model
Pole setting for alignment	Matches resolver speed

A 4 pole resolver is a 2 speed resolver and so on, the speed being the number of pole pairs. Servo motors commonly use 1, 2, 3 and 4 speed resolvers; a 4 speed resolver is normally used on an 8 pole motor.

02Faults

How Multi-speed resolver encoders usually fail

Open or shorted excitation, sine or cosine winding
Connector or cable fault
Distorted signals from wrong excitation, with jumpy angle readings or dead spots
Sine or cosine leads reversed, giving the wrong direction

02+Alarms

Multi-speed resolver alarms and error codes: what they mean and what to check

These are the alarms most often seen with the Multi-speed resolver feedback device, with what each usually means and what to check first. Many encoder alarms are caused by the cable, connector or battery, not the encoder, so the checks below can save a repair.

Alarm	Usually means	Check first
Loss of signal	The sine or cosine amplitude is too low or missing	Open winding or broken cable; check the excitation
Degradation of signal	Signal level outside the normal range or sine and cosine unequal	Damaged winding, bad joint or shield problem
Loss of tracking	The converter cannot follow the shaft	Noise or a disturbed signal; also speed beyond the converter range
Excitation fault	The reference supply is missing or shorted	Measure the reference winding and cable
Cable break or open winding alarm	The drive reports a resolver wire break	Measure each winding at the drive end of the cable
Position jump or wrong electrical angle	Alignment offset wrong, or the resolver speed does not match the motor poles	Align the resolver to the rotor; check the pole count

Resolver-to-digital converters in drives report these as loss of signal, degradation of signal or loss of tracking, under different alarm numbers for each drive brand. Alarm numbers and wording change with drive series and firmware, so check the manual for your drive. Drive brand names are used only to identify alarm lists. Star Automations is an independent multi-brand repair company and is not an OEM service centre.

Typical causes and checks

Alarm at every power-up: reseat the connector at both ends, check the encoder supply at the motor end, and look for a broken wire.
Alarm only when the axis moves or the cable flexes: suspect a break inside the cable chain, or a shield that has come loose.
Alarm after coolant, washdown or rain: look for moisture or corrosion in the connector and behind the encoder cover.
Alarm at random with other drives running: check earthing and shield clamps, and keep the feedback cable away from power cables.
Alarm after a motor, encoder or drive change: check the type, the motor data in the drive, and the encoder alignment.

Encoder, cable or drive?

Swap in a known-good feedback cable first. If the alarm stays, move the motor to another axis if the drives are the same type. If the alarm follows the motor, the encoder or motor needs testing. If it stays on the axis with a good motor and cable, the drive needs testing. We test the encoder, the motor and the drive, so send the nameplate if you are not sure which it is.

03Process

How the repair is done

Receive and identify
We read the nameplate and encoder label and confirm the exact type.
Test
Count per turn, data status, alarm flags and, where fitted, incremental lines are checked on the bench.
Repair or replace
Board, connector or sensor faults are repaired; a matched encoder is fitted where repair is not sensible.
Align
Commutation is set to the rotor and checked at every pole pair using the electrical angle.
Verify and report
The motor is run on the bench and the readings are recorded in the report.

See encoder alignment, memory programming and replacement.

04Related

Other Resolver encoders we repair

05FAQ

Questions

What do encoder alarms on a Multi-speed resolver usually mean?

Most fall into four groups: no communication, corrupted data, a fault reported by the encoder itself, and a position or commutation mismatch. The alarm table on this page lists the common codes and the first check for each.

How can I tell whether the Multi-speed resolver encoder, the cable or the drive is at fault?

Swap in a known-good feedback cable, then move the motor to another axis if possible. If the alarm follows the motor, the encoder needs testing; if it stays on the axis, the drive does. A cable or battery fault can be fixed without sending anything.

Can you repair a Multi-speed resolver encoder?

Yes. We test the position count and status, repair or replace the encoder, align it to the rotor and run the motor. We repair Resolver units; Star Automations is an independent multi-brand repair company and is not an OEM service centre.

What is a 4 speed resolver?

An 8 pole resolver whose angle goes through 360 degrees four times per revolution.

What excitation do you use?

Adjustable up to 8 V peak and from 1 to 20 kHz, set to avoid waveform distortion.

What should I send for a Multi-speed resolver enquiry?

A clear photo of the motor nameplate and, if the cover is off, the encoder label. You can send the motor or only the encoder.

06Enquiry

Send the nameplate or encoder label

A clear photo of the motor nameplate and, if the cover is off, the encoder label is enough to start. We reply with whether it can be repaired and a quote.

→How it works

From nameplate photo to a tested motor in 7 steps

One route for servo motors, encoders and drives. You see the price before any work starts, and the report before the unit leaves our bench.

1 · Nameplate photoSend it on WhatsApp or the form
2 · Repairable? QuoteUsually the same working day
3 · Courier or pickupThe unit reaches our bench
4 · Bench diagnosisInsulation, windings, brake, encoder
5 · RepairFailed parts, bearings, seals, brake
6 · Align and run-testEncoder aligned; no-load and load run
7 · Report and dispatchPrinted test report with the unit
Line down?Servo Swap ships a tested unit first. How Servo Swap works

EmergencySame day*

Urgent3 working days

Standard7 working days

*Where the fault and parts allow. Turnaround counts from when the unit reaches our bench and the quote is approved.

Start with step 1 WhatsApp the nameplate