Static and dynamic presentation 05 2009

S tatic & Dynamic Mo to r Te s ting Dre w No rman Ap p lic atio ns Eng ine e r VIBRATION INS TITUTE Pie d m o nt Chap te r #14 2009 Annual S e m inar Mo to r Failure Are as IEEE Study (Early 1990’s) EPRI Study (Mid 1990’s) S tatic Mo to r Te s ting Intro to S tatic Mo to r Mo nito ring De fining S tatic (Off-Line ) Ele c tric Mo to r Te s ting WHAT IS IT: Me a s uring a nd tra cking e le ctrica l prope rtie s of the winding circuit in a n e ffort to de te rmine its he a lth a nd re lia bility while the motor is de e ne rgize d HOW: Low Volta ge Te s ting Me a s uring s pe cific e le ctrica l pa me te rs a t or be low na me pla te volta ge s to de te rmine a cha nge in the e le ctrica l circuit prope rtie s High Volta ge Te s ting Te s ting motor ins ula tion a t volta ge le ve ls s imila r to thos e the motor e ncounte rs in it’s norma l e nvironme nt Winding De s ig n Ra ndom Winding (Mus h Winding) Form Coil Te s ting Ins ulatio n S ys te ms • Multime te rs • Me g-Ohm-Me te r • Re s is ta nce Me te rs (DLRO, Bridge s ) • Low volta ge circuit e va lua tion (i.e Ca pa cita nce , Inducta nce ) • High P ote ntia l Te s t – AC-DC • S urge Te s ting • Corona Te s ting • P a rtia l Dis cha rge De te ction • Infra re d, Ultra s onic, Vibra tion To pic s o f Dis c us s io n Ins ula tion S tre ngth Fa ilure Me cha nis ms Te s ting The ory • Te s t P a me te rs • P a ss / Fa il Crite ria Me thods of Te s ting P re dictive Indica tors in Ele ctrica l Motor Te s ting Die le c tric S tre ng th o f Go o d Ins ulatio n Pro pe rtie s o f the Die le c tric s Dielectric Strength Puncture/Breakdown Wire fo r a 460V AC mo to r has 6000VAC ins ulatio n c apability (NEMA MG-1) 8400 Volts Peak 6000V RMS Or: 6000 AC = 8400VDC Mo to r failure are as : Be aring s harm * BPFO ± * RPM Mo to r Failure Are as : Be aring s 5hp po le harm * BPFO ± * Fund Fre q 3D De mo dulatio n: n Bd Outer Race ( BPFO) = f (1 − Cosβ ) Pd BPOF: 107Hz Ec c e ntric ity: De mo dulate d To rque * Ele c tric al 50Hz po le 300hp * Ele c tric al De mo dulate d s ig nals : To rque vs Curre nt Bad Motor #1 Bad Motor #2 Good Motor #1 Good Motor #2 Factor Demodulated Torque Demodulated Current 1* RPM 2* RPM 1* RPM 2* RPM 3.47E-05 7.94E-05 0.00324 0.03150 4.26E-05 7.96E-05 0.00398 0.03091 2.96E-05 1.35E-05 0.00245 0.03109 3.46E-05 1.42E-05 0.00308 0.03057 1.20 5.90 1.31 1.01 Co nc lus io ns : • De mo dulate d Curre nt me tho d e s no t ag re e with vibratio n’s me tho ds • De mo dulate d To rque re ac ts like vibratio n’s me tho ds • This me tho d is inde pe nde nt o f Mo to r de s ig n • This me tho d e s no t dis ag re e with IEEE mo to r s c ie ntis t’s re s e arc h 3D De mo dulatio n: Ec c e ntric ity in mo to r ‘ide ntica l’ 50Hz pole Ecce ntricity typica l @: • 1x, 2x (25Hz, 50Hz) One ‘good’, one ‘ba d’ 3D De mo dulatio n: Ec c e ntric ity in mo to r ‘Go o d’ ‘Bad’ VFD: Variable Fre que nc y Conve yor drive 60 hp 1200 rpm • Fre que nc y c o ntro l • S pe e d c o ntro l • To rque c o ntro l • Ve c to r drive • V o ve r f • Fe e dbac k lo o p VFD: What is g o ing o n? Co nve yo r Drive 60 hp 1200 rpm • Bre aking • Ge ne rato r • Ove r rate d • Os c illating • Flawe d c o ntro l lo o p de s ig n Te s ting Mo to rs * *LTEE Effe c t o f Gre as e o n No Lo ad Lo s s e s 60 Hp, Po le * *GE Trans ie nt Analys is Trans ie nt Analys is VFD: Typic al is s ue s : Co mmo n pro ble ms in the fie ld Ove r volta ge s pike s S ft volta ge s Be a ring fa ilure s Volta ge dis tortion on input Volta ge dis tortion on output Va ry output volta ge s with fre q Thank Yo u ... natural consequence of motion and it was found when the likely points were located…” D.E Crawfo rd Mo vie B.K Gupta, B.A Llo yd, G.C S to ne , D.K S harma, N.E Nils s o n, and J.P Fitzg e rald, “Turn... t Ce ll Line r Phas e Ins ulatio n Slot liner is 20,000 VDC Nomex-Mylar-Nomex Single slot in a random wound Φ Motor •Co mbine d Ins ulatio n to Gro und is 8400 VDC + 20,000 VDC = 28,400 VDC Ins... hanis m o f Mo to r Failure s ” Ge ne ral Ele c tric Co mpany, 75CH1014-0-EI-19 “…Looseness, motion and wear develop as the result of certain stresses applied to the motor windings by the service