CBB61 3μF Motor Start & Run Capacitor

Model & Specification Explanation

Definition of CBB61 Model

CBB: Metallized polypropylene film capacitor (non-polar, low loss, self-healing and explosion-proof built-in)
61: Standard series of plastic-cased lead-out capacitors specially for starting/running single-phase AC motors
3μF: Nominal capacitance of 3 microfarads; mainstream tolerances in the industry: ±5% (Grade J) / ±10% (Grade K)
Standard rated voltage: 450VAC (universal model for domestic 220V mains power), compatible with 50/60Hz power supply
Core Electrical Specifications

Item	Standard Specification
Nominal Capacitance	3.0μF
Capacitance Tolerance	±5% (Grade J) / ±10% (Grade K)
Rated AC Voltage	450VAC (Replacement voltage shall not be lower than 400VAC)
Applicable Frequency	50Hz / 60Hz
Dielectric Material	Metallized polypropylene film
Dissipation Factor tanδ	≤0.002 (ultra-low heat generation, suitable for long-term continuous operation)
Operating Temperature	-40℃ ~ +70℃ (Climate Class 40/70/21)
Structure	Black flame-retardant plastic housing, epoxy resin sealing, double wire leads (non-polar)
Safety Features	Self-healing after overvoltage breakdown, explosion-proof pressure relief structure, compliant with UL94 V0 flame retardant standard
Service Life	Class B, 10,000 hours of continuous operation
Applicable Standards	GB/T 3667.1, IEC60252-1

III. Working Principle

A single-phase asynchronous motor cannot start on its own. This capacitor is connected in series with the motor auxiliary winding to generate a rotating magnetic field via phase shift and provide starting torque. During operation, it continuously maintains motor torque, improves power factor and reduces winding heat generation.

Fault manifestations without a functional capacitor: The motor hums after power-on, only rotates when manually pushed, runs at low speed with insufficient power, and shuts down frequently.

Full Application Scenarios (3μF Matches Low-Power Fans)
Household Ventilation Equipment (Most Widely Used)

Floor fans, desk fans, wall fans, ceiling fans, circulation fans

Main fans for kitchen range hoods, small ventilators, bathroom exhaust fans

Cross-flow fans of indoor air conditioners, small cooling fans, portable air conditioner fans

Small Household Appliance Motors

Drainage motors and auxiliary dewatering fans of small washing machines

Centrifugal fans for dehumidifiers and air purifiers

Air supply motors for small humidifiers, space heaters and warm air blowers

Small Industrial Single-Phase Equipment

Small cooling fans for machine tools, heat dissipation fans for electrical control cabinets

Small 220V clean water pumps, atomizing water pumps, miniature air compressors

Small heat dissipation fans for production lines, cooling fans for food processing equipment

HVAC & Commercial Equipment

Small indoor fans of central air conditioners, small motors for air curtains

Heat dissipation fans for convenience store refrigerators and display freezers

Mandatory Requirements for Model Selection & Replacement
Capacitance must be matched: Only 3μF is acceptable; 2.5μF or 4μF cannot be used as substitutes

Smaller capacitance: Insufficient starting torque, low rotating speed, motor overheating and winding burnout

Larger capacitance: Excessive current leading to rapid burnout of motor coils

Rated voltage ≥450VAC: Low-voltage models of 250V/330V are forbidden for replacement, as they tend to bulge and burst
Must adopt CBB61 film capacitors; electrolytic capacitors are not allowed (electrolytic capacitors are polar and prone to liquid leakage under AC power)
Lead length and mounting holes shall be matched as required; non-polar with no positive/negative wiring distinction
Typical Fault Phenomena & Solutions

Fault Phenomenon	Root Cause of Capacitor Failure	Solution
Fan hums after power-on and fails to rotate unless manually pushed	Capacitance degradation, capacitance drops below 2μF	Directly replace with CBB61 3μF/450V
Obviously reduced rotating speed and air volume	Capacitor aging and insufficient capacitance	Replace with a new capacitor
Circuit breaker trips or fuse blows within several seconds after power-on	Internal short-circuit breakdown of capacitor	Cut off power for replacement and inspect motor windings
Bulged housing, glue leakage, blackening and overheating	Long-term overheating or insufficient withstand voltage	Replace immediately and check whether the motor is stuck
Intermittent rotation and insufficient power	Poor internal contact of capacitor	Replace with a brand-new capacitor

VII. Safety Key Points for Installation & Replacement

Cut off power before operation! Short-circuit the two leads with a screwdriver for full discharge to prevent electric shock.
The two leads are non-polar and can be connected to either end of the motor auxiliary winding arbitrarily.
Fix the capacitor far away from heat-generating parts of the motor to avoid accelerated aging caused by high temperature.
Wrap wiring terminals with insulating materials to prevent short-circuit and sparking.
Do not squeeze or bend the capacitor housing to avoid sealing damage and moisture ingress.

VIII. Unsuitable Application Scenarios

High-power compressors and air compressors (large-capacity CBB60 capacitors are required)
DC motors and DC circuits of inverters (designed exclusively for AC, not for long-term DC operation)
High-temperature enclosed equipment (custom high-temperature resistant models are required for environments above 75℃)