MYCOM CS1290-E10 Slide Valve Potentiometer

MYCOM CS1290-E10 Slide Valve Potentiometer (Japan Servo EP45 1kΩ)

The MYCOM CS1290-E10 is an OEM-spec conductive plastic rotary potentiometer engineered by Japan Servo Co., Ltd. (Type EP45) specifically for Mayekawa / MYCOM screw refrigeration compressors. Installed within the unloader indicator assembly, this instrument translates mechanical axial stroke and angular movement of the capacity control slide valve into a linear electrical resistance output (0 to 100% load feedback).

Designed to endure continuous exposure to marine and industrial environments, synthetic refrigeration compressor oils, and wide thermal cycles, the conductive plastic element delivers low contact resistance variation, zero backlash, and tight linearity (±0.35%) across its operational range.

Model Details

• Assembly Part Number: MYCOM CS1290-E10
• Internal Sensor Component: Japan Servo Co., Ltd. Type EP45
• OEM Manufacturer: Mayekawa Mfg. Co., Ltd. (MYCOM) / Japan Servo (Nidec)
• Nominal Resistance: 1,000 Ω (1 kΩ ±10%)
• Independent Linearity: ±0.35%

Technical Details

Terminal Allocations & Wiring Schematic

• Terminal 1 (CW End / Ground / 0 V): Negative supply / Reference low from controller bridge circuit.
• Terminal 2 (Wiper Output / Signal): Variable voltage tap conveying capacity position proportional to unloader push rod extension.
• Terminal 3 (CCW End / +Excitation): Regulated DC supply (+5 VDC, +10 VDC, or +24 VDC circuit feed depending on control board spec).

Compatible Equipment Models

• MYCOM Single-Stage Screw Compressors: 160S / 160M / 160L, 200S / 200M / 200L, 250S / 250M / 250L, 320S / 320L
• MYCOM Compound / Two-Stage Screw Compressors: 2016C, 2520C, 3225C series
• Controller Systems: Compatible with MYPRO-CP series (CP-I, CP-II, CP-III, CP-IV), MYPRO-Touch, and third-party PLC-based compressor capacity automation racks.

Key Features

1. Conductive Plastic Track: Yields smooth voltage resolution, near-infinite mechanical life, and reduced contact noise compared to wirewound elements.
2. Calibrated Linearity (±0.35%): Ensures accurate 0–100% capacity feedback, preventing unloader over-travel and hunting.
3. Marine-Grade Vibration Immunity: Robust internal multi-finger wiper design maintains contact integrity under the constant vibration typical of marine auxiliary machinery spaces.
4. Drop-In Mechanical Fit: Precision machined pilot face and shaft dimensions mate with the unloader indicator gear drive without housing modifications.
5. Stable Oil & Temperature Tolerance: Internal seals resist degradation from ammonia (R717), hydrofluorocarbons (R404A, R507, R134a), and POE/mineral refrigeration oils.

Applications

• Marine cargo hold refrigeration plants (Reefer vessels and LPG/ammonia gas carriers)
• Fishing trawler blast freezers, slurry ice generation, and brine chilling units
• Cold storage logistics facilities and rapid blast freezing tunnels
• Industrial food and beverage processing (dairies, breweries, meat packing facilities)
• Petrochemical process refrigeration and offshore vapor recovery units (VRU)

Part Number Cross-References

• OEM Part Number: CS1290-E10
• Internal Sensor Component: Japan Servo EP45 (1kΩ, Lin ±0.35%)
• Nidec Replacement Ref: Nidec Servo EP-45 / CS-1290
• Alternative Reference Codes: EP45-1K, CS1290E10-MYC

Frequently Asked Questions

Can the Japan Servo EP45 sensor be installed as a direct replacement for an existing CS1290-E10 assembly?

Yes. The CS1290-E10 assembly uses the Japan Servo EP45 conductive plastic potentiometer as its core sensor element. It provides the matching 1 kΩ resistance, ±0.35% linearity, and shaft/mounting geometry.

Why is my compressor display fluctuating erratically between 40% and 60% capacity?

This behavior typically indicates local wear, pitting, or carbon accumulation on the conductive track at the compressor’s most frequent operating load point. Replacing the unit restores linear voltage output and stops the unloader solenoid valves from hunting.

What is the recommended excitation voltage for the CS1290-E10?

The potentiometer operates reliably on 5 VDC, 10 VDC, or 24 VDC regulated inputs supplied by the compressor microprocessor board (e.g., MYCOM MYPRO series), drawing minimal current across its 1,000 Ω track.

Does this potentiometer include internal mechanical stops?

The Japan Servo EP45 has a 360° continuous mechanical rotation without physical end-stops, paired with a 340° active electrical angle. The mechanical travel is limited by the external compressor unloader indicator gearbox, preventing internal sensor shearing during full-stroke movement.