Danfoss 117U5017 start capacitor for single-phase hermetic refrigeration compressors. Capacitance: 80 microfarads (uF). Voltage rating: 260 V AC. Function: provides the phase shift required at start-up on a single-phase capacitor-start (CSR) or PSC / CSCR hermetic compressor motor, allowing sufficient starting torque to overcome the compressor's initial resistance. Once the motor reaches ~75 percent of rated speed, the start capacitor is switched out of the circuit by a start relay (potential relay or current relay) or PTC starter — the capacitor is DESIGNED for INTERMITTENT service, not continuous energisation. Applications: hermetic reciprocating refrigeration compressor start assist (commercial refrigeration, ice machine, walk-in cooler, small chiller), light-commercial air-conditioning compressor start assist, and single-phase induction motor start circuits in refrigeration cabinet equipment. Typical fitment: replaces a failed or aged start capacitor in service — cause of failure is usually cumulative energisation cycles (each start is a duty cycle for the electrolytic capacitor) plus operating-temperature stress. Scheduled replacement at compressor overhaul or when the compressor exhibits hard-start behaviour (audible motor grunt / slow spin-up). IMPORTANT SAFETY: an electrolytic start capacitor stores DC potential after the compressor is de-energised. ALWAYS discharge the capacitor across a 10-20 kilo-ohm resistor (bleed resistor) before handling terminal connections. Do NOT short-circuit the terminals with metal — that shocks the dielectric and can damage the capacitor. The 117U5017 sits in the Danfoss electrolytic start-capacitor family alongside a range of capacitance / voltage combinations for different compressor sizes. Higher-capacitance variants at the same voltage suit larger displacement compressors; higher-voltage variants (e.g. 330 V AC) suit line-voltage regions above 240 V nominal. Check the OEM compressor datasheet for the correct capacitance and voltage per compressor model.