a practical introduction to electric discharge machining, or “bearing currents” in bearings –...

8/12/2019 A Practical Introduction to Electric Discharge Machining, Or Bearing Currents in Bearings Wha

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EDM Physics and RealityEDM Physics and Reality

GKE ELEKTRONIK AB, GRANBERGSDAL, SWEDEN. !" #$" %&&"" GKE'SWIPNET.SE SK(PE) SKOGSG*RRA %

A +actical int-dcti-n t- Electic Discha/e Machinin/, -0Beain/ 1ents0 in Beain/s 2hat it is, h-2 t-

dia/n-se, a3-id and 4iti/ate.


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GKE ELEKTRONIK AB, GRANBERGSDAL, SWEDEN. !" #$" %&&"" GKE'SWIPNET.SE SK(PE) SKOGSG*RRA &

1-ntentsInt-dcti-n. EDM, PWM.

Beain/ cent da4a/es EDM incease. PWM is the 4ain case.

P-5le4s e6ist in all 4-t- si7es 4-e - less

EDM cl-se8+

The 9- 9aile 4echanis4s

Is-lati-n, 9ilte, sha9t /-ndin/, cea4ic 5alls :hy5id 5eain/s;

EDM si/nate

1ases


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GKE ELEKTRONIK AB, GRANBERGSDAL, SWEDEN. !" #$" %&&"" GKE'SWIPNET.SE SK(PE) SKOGSG*RRA 8d-2n 3-lta/e) Oil 9il4 thic>ness

and st-chastically -ccin/ i4+ities in s9aces and -il.

A si4+le test cicit can 5e sed t- stdy5ea>8d-2n 3-lta/e. See 9i/e t- le9t.Reslts sh-2n ae si4lated +e9-4anceand 4ease4ents -n a eal "&%! DGBB.

Si4lated

Real


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GKE ELEKTRONIK AB, GRANBERGSDAL, SWEDEN. !" #$" %&&"" GKE'SWIPNET.SE SK(PE) SKOGSG*RRA !

It is 3ey ae that y- 9ind a 5eain/ 2ith a D1 3-lta/ea++lied t- it li>e sh-2n in +e3i-s 9a4e. The 3-lta/ed-es, -9 c-se, c-4e 9-4 -the s-ces. Bt the D15ea>8d-2n test illstates 2hat an EDM 5ea>8d-2n isand it is a /--d statin/ +-int 9- the 9-ll-2in/ discssi-n.

The 4-st c-44-n s-ce -9 sha9t 3-lta/e is n-2 +aasiticc-+lin/ 9-4 the stat- -9 PWM 9ed asynch-n--s4-t-s. An e6a4+le -9 a PWM 3-lta/e and the esltin/4-t- cent is /i3en in ne6t 9a4e.


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GKE ELEKTRONIK AB, GRANBERGSDAL, SWEDEN. !" #$" %&&"" GKE'SWIPNET.SE SK(PE) SKOGSG*RRA #

M-t- cent

M-t- 3-lta/e


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GKE ELEKTRONIK AB, GRANBERGSDAL, SWEDEN. !" #$" %&&"" GKE'SWIPNET.SE SK(PE) SKOGSG*RRA "

Beain/ da4a/es incease PWM is the cl+itThee ae a 9e2 eas-ns 9- electical da4a/e t- 5eain/s.

The 4-e c-44-n ae)

Electic 2eldin/ 2ith c-44-n lead a++lied t- 2-n/ s+-t

0L-c-4-ti3e /-ndin/0 th-/h 5eain/s

1iclatin/ cent th-/h sha9t and 5eain/s

Elect-static discha/e :EDM; th-/h 5eain/

Inceased se -9 ?@Ds 2ith PWM inceases EDM andis n-2 the d-4inatin/ eas-n 9- 5eain/ da4a/es


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GKE ELEKTRONIK AB, GRANBERGSDAL, SWEDEN. !" #$" %&&"" GKE'SWIPNET.SE SK(PE) SKOGSG*RRA

?A1 Middle Ran/e i/h P-2e

T-tal n45e

-9 +-5le4s

P-5le49e=ency

P-5le4s e6ist in all 4-t- si7es n-t -nly la/e -nes.


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GKE ELEKTRONIK AB, GRANBERGSDAL, SWEDEN. !" #$" %&&"" GKE'SWIPNET.SE SK(PE) SKOGSG*RRA $

?A1 Middle Ran/e i/h P-2e

Di99eent +-5le4s in di99eent 4-t- si7es

1a+aciti3e 1-+lin/

@a4e ?-lta/e

Indcti3e 1-+lin/


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GKE ELEKTRONIK AB, GRANBERGSDAL, SWEDEN. !" #$" %&&"" GKE'SWIPNET.SE SK(PE) SKOGSG*RRA C

EDM 1l-se8+Thee ae 9- +ee=isites 9- EDM :Electic Discha/e

Machinin/;

1a+acitance

1ha/e :3-lta/e ac-ss ca+acitance;

Is-lati-n

Is-lati-n 9aile

EDM can 5e a3-ided 5y eli4inatin/ -ne :- se3eal;-9 these +ee=isites


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EDM 1l-se8+Ene/y in the ac e3a+-ates steel s- that a cate is ceated.

> .% 2hen nits ae F4, ? and n@


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GKE ELEKTRONIK AB, GRANBERGSDAL, SWEDEN. !" #$" %&&"" GKE'SWIPNET.SE SK(PE) SKOGSG*RRA %%

EDM 1l-se8+Test 2ith 04ac-8ene/y0. Mic-9aads and hndeds -9 3-lts

+-dce shall-2 cates. Bt the +inci+le h-lds 4-e ca+acitance

and 4-e 3-lta/e ceate la/e cates


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GKE ELEKTRONIK AB, GRANBERGSDAL, SWEDEN. !" #$" %&&"" GKE'SWIPNET.SE SK(PE) SKOGSG*RRA %&

EDM 1l-se8+N-4al ca+acitance 3ales :% % n@; and n-4al 3-lta/es :# %#

?; +-dce cates in the % 4ic-n an/e. Th-se sh-2n t- the le9t

ae a5-t that si7e.

Ty+ical 2ash85-ad +atten sh-2n t- the i/ht. The +atten has

n- c-nnecti-n t- in3ete 9e=ency - s+eed a +-+la and

c-44-n 4isndestandin/


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GKE ELEKTRONIK AB, GRANBERGSDAL, SWEDEN. !" #$" %&&"" GKE'SWIPNET.SE SK(PE) SKOGSG*RRA % at these in the 9-ll-2in/ 9a4es.


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GKE ELEKTRONIK AB, GRANBERGSDAL, SWEDEN. !" #$" %&&"" GKE'SWIPNET.SE SK(PE) SKOGSG*RRA %!

The 9- 9aile 4echanis4s %. 1a+aciti3e 1-+lin/.

PWM 3-lta/e 9-4 the ?@D has 3ey stee+ ed/es.

The c-44-n 4-de 3-lta/e :le9t; is ca+aciti3ely

c-+led 9-4 stat- t- -t-. The esltin/ 3-lta/e

ac-ss the 5eain/ eslts in EDM and destcti-n.


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GKE ELEKTRONIK AB, GRANBERGSDAL, SWEDEN. !" #$" %&&"" GKE'SWIPNET.SE SK(PE) SKOGSG*RRA %#

1a+aciti3e c-+lin/

5-th sha9t ends 4-3ein8+hase.

Sha9t 3-lta/e is

sa4e sha+e asc-44-n84-de3-lta/e

The ca+aciti3e 3-lta/edi3ide edces sha9t

3-lta/e t- +ecents -9c-44-n84-de 3-lta/e,




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GKE ELEKTRONIK AB, GRANBERGSDAL, SWEDEN. !" #$" %&&"" GKE'SWIPNET.SE SK(PE) SKOGSG*RRA %"

One inslated 5eain/ :- -ne hy5id 5eain/; is -9 n- se in a sitati-nli>e this. The eslt is that -t- discha/es in the -the 5eain/.The 5eain/ 2ith the l-2est 5ea>8d-2n 3-lta/e :3aies st-chastically

-3e ti4e; 5ea>s d-2n 9ist. I9 theeHs -nly -ne 5eain/, the 0ealiest05ea>8d-2n 3-lta/e /ets hi/he. And, since ene/y is +-+-ti-nal t-3-lta/e s=aed, discha/e ene/y and da4a/e inceases.


Inslated 5eain/



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An e6a4+le -9 ca+aciti3e c-+lin/. This is a n-n8ty+ical case in a athela/e 4-t-. The 9act that 5-th sha9t ends ae in8+hase is i4+-tant. TheND 5eain/ is inslated. This 4eans that the sha9t 3-lta/e d-esnHt /- t-7e- and stays thee, 5t -scillates 2ith a hi/h 9e=ency dete4ined 5y

5eain/ ca+acitance and 0l-cal0 indctance. The -t- indctance andca+acitance act as a l-2+ass 9ilte the -scillati-ns can hadly 5e seenin tace A.



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GKE ELEKTRONIK AB, GRANBERGSDAL, SWEDEN. !" #$" %&&"" GKE'SWIPNET.SE SK(PE) SKOGSG*RRA %$

The 9- 9aile 4echanis4s &. Indcti3e 1-+lin/.

Sha9t 3-lta/e

@l6 a-2

The s4 -9 the thee +hases that 4a>e + a PWM 3-lta/e d-es

n-t e=al 7e-. A esltin/ n-n87e- stay cent is /-in/ 9-4stat- 2indin/ 3ia ca+acitance t- /-nd. The stay cent in3->esa 4a/netic 9ield that :c-ntay t- the sine 9ield; indces a 3-lta/e inthe 4-t- sha9t. A 3-lta/e that can each " ? +> - 4-e in la/e4achines. The sha9t end 3-lta/es 4-3e -t -9 +hase.


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GKE ELEKTRONIK AB, GRANBERGSDAL, SWEDEN. !" #$" %&&"" GKE'SWIPNET.SE SK(PE) SKOGSG*RRA %C


P-siti3e 3-lta/ee6csi-n

Ne/ati3e 3-lta/ee6csi-n

Sha9t 4ean 3-lta/e is 7e-. E6csi-ns sally /- t- tens -93-lts. Plse 2idth is in 4ic-sec-nds an/e. RMS 3-lta/e,thee9-e, sally is 5el-2 % ?. Mlti4etes can n-t 5e sed t-stdy sha9t 3-lta/e. *se an -scill-sc-+e 2ith at least & M75and82idth.


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GKE ELEKTRONIK AB, GRANBERGSDAL, SWEDEN. !" #$" %&&"" GKE'SWIPNET.SE SK(PE) SKOGSG*RRA &


A ty+ical PWM EDM sitati-n. Le9t sha9t end /-es ne/ati3entil a 5ea>8d-2n -ccs. Le9t end then 4-3es in +-siti3e

diecti-n t- 7e- 3-lts. In 9act the 2h-le -t- and sha9t4-3es in +-siti3e diecti-n s- that the i/ht sha9t end /-ese3en hi/he than it 2as. S-4eti4es casin/ a sec-nday5ea>8d-2n in that 5eain/.


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GKE ELEKTRONIK AB, GRANBERGSDAL, SWEDEN. !" #$" %&&"" GKE'SWIPNET.SE SK(PE) SKOGSG*RRA &%

R-t- ca+acitance is a >ey +aa4ete. E3en 2ith a c-4+letelyinslated i/ht end 5eain/, the 3-lta/e e6csi-n at the le9t end

2-ld 5e the sa4e and als- the esltin/ 5ea>8d-2n.An inslated 5eain/ is sally e99ecti3e -nly in the 0-ld89ashi-ned0 4a/netic i45alance sitati-n. That is n-t a 3eyc-44-n sitati-n in 4-den 4-t-s 2ith t-dayHs ti/ht4a9actin/ t-leances.



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GKE ELEKTRONIK AB, GRANBERGSDAL, SWEDEN. !" #$" %&&"" GKE'SWIPNET.SE SK(PE) SKOGSG*RRA &&


An inslated 5eain/ has 5een installed :yell-2 inslati-n;.As sh-2n, the le9t 5eain/ d-es n-t 0>n-20 that thee is an

inslated 5eain/. The 3-lta/e e6csi-n is sa4e as 5e9-eand 5ea>8d-2n als-. 1ent is NOT ciclatin/ in sha9t it is-nly a =esti-n -9 discha/in/ -t- ca+acitance. Bt, theinslati-n sally +-l-n/s se3ice li9e -9 the inslated5eain/. N-t the n-n8inslated.


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GKE ELEKTRONIK AB, GRANBERGSDAL, SWEDEN. !" #$" %&&"" GKE'SWIPNET.SE SK(PE) SKOGSG*RRA &8d-2n in++e tace is e9lected in a si4ila 3-lta/e deceaseJinceasein l-2e tace.


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GKE ELEKTRONIK AB, GRANBERGSDAL, SWEDEN. !" #$" %&&"" GKE'SWIPNET.SE SK(PE) SKOGSG*RRA &!

The 9- 9aile 4echanis4s e this.


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The 9- 9aile 4echanis4s !. E6tenal Ene/y.

E6tenal ene/y is al4-st al2ays ti5-electic ene/y - staticelecticity. Ti5-electicity is 2hat y- /et 2hen 55in/ t2-4ateials a/ainst each -the. Thin> 1at s>in and E5-nite. Inslatin/-ils and s-4eti4es e3en ai can +-dce static electicity. Li/htnin/is a /--d, alth-/h s-4e2hat e6a//eated, e6a4+le. Sitati-nsthat 1AN +-dce ti5-electicity ae)

Belt di3es

P4+s and 9iltes 9- -ils. Synthetic -ils ae citical.

@ast :diect di3en; 9ans.

Sitati-ns 2hee dy 4ateial is c-n3eyed. Wies in +a+e 4achine

dye secti-ns is a +actical e6a4+le.

Thee ae indicati-ns that Wind T5ines 4ay ha3e this +-5le4.


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GKE ELEKTRONIK AB, GRANBERGSDAL, SWEDEN. !" #$" %&&"" GKE'SWIPNET.SE SK(PE) SKOGSG*RRA &"

Miti/ati-n G-ndin/ Bshes

G-ndin/ 5shes ceate a +aallel cent +ath s- that the5eain/ is sa3ed. N-t -nly that they als- +e3ent that a cha/eis 9-4ed. G-ndin/ 5shes ae -9ten 3ey e99ecti3e, 5t s-4e

e6+etise 4ay 5e needed 2hen a++lyin/ the4 t- la/e 4achines.They can 5e ++-se85ilt nits li>e the R-c>2ell e6a4+le -si4+le ad h-c de3ices li>e the -ne t- the i/ht.They need cae, ins+ecti-n and 4aintenance.


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GKE ELEKTRONIK AB, GRANBERGSDAL, SWEDEN. !" #$" %&&"" GKE'SWIPNET.SE SK(PE) SKOGSG*RRA &$

Miti/ati-n Inslati-n

Endshield

Inslatin/

4ateial

Steel

in/

M-di9yin/ end shield s- that 5eain/ is inslated is-ne 4eth-d that has 5een sed. It is athe c-stly, 5tstandad 5eain/s can 5e sed n- need t- st-c>s+ecials.

EDM Ph i d R li


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GKE ELEKTRONIK AB, GRANBERGSDAL, SWEDEN. !" #$" %&&"" GKE'SWIPNET.SE SK(PE) SKOGSG*RRA &C

Miti/ati-n Inslati-n

S+tteed Al&O


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EDM Ph sics and RealitEDM Physics and Reality


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GKE ELEKTRONIK AB, GRANBERGSDAL, SWEDEN. !" #$" %&&"" GKE'SWIPNET.SE SK(PE) SKOGSG*RRA t- D1 lin>.

Red ?@D -t+t Ble 4-t- 3-lta/e



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Thee t--ids cana5s-5 " F?s

A4-+h-s s-9t 4a/netic 4ateial has 3ey /--d 4a/netic+-+eties. That is als- te 9- s-4e i-n +-2de in/s.@eites ha3e 4ch l-2e +e4ea5ility and d- n-t +e9-42ell. The te4 0@eite Rin/0 is -9ten sed t- desci5e thesen-n89eite t--ids.

Miti/ati-n @iltes



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GKE ELEKTRONIK AB, GRANBERGSDAL, SWEDEN. !" #$" %&&"" GKE'SWIPNET.SE SK(PE) SKOGSG*RRA 2ell At-4ati-n site.

Miti/ati-n



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EDM Physics and Realityy y

GKE ELEKTRONIK AB, GRANBERGSDAL, SWEDEN. !" #$" %&&"" GKE'SWIPNET.SE SK(PE) SKOGSG*RRA dia/a4 9- the BEPPE:Beain/ Pedict-;. A6iliay

9ncti-ns li>e 4ease4ent -9synch-n-s s+eed, sli+ andte4+eate ae sh-2n.

EDM Si/nate and Mease4ent



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y yy y

GKE ELEKTRONIK AB, GRANBERGSDAL, SWEDEN. !" #$" %&&"" GKE'SWIPNET.SE SK(PE) SKOGSG*RRA !


Thee ae se3eal +-t-ty+e i4+le4entati-ns -9 the Beain/Pedict-. The dis+lay -9 an ealy nit is sh-2n.

PPS Plses Pe Sec-nd

& M?Js

M % M?JsL # M?Js



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y yy y

GKE ELEKTRONIK AB, GRANBERGSDAL, SWEDEN. !" #$" %&&"" GKE'SWIPNET.SE SK(PE) SKOGSG*RRA !%


An-the 3esi-n c-ntains disci4inat- and c-ntes in a se+aatenit that c-44nicates 2ith a P1 3ia y+ete4inal - -theasynch-n-s +-t-c-l. A +int-t e6a4+le is sh-2n 5el-2.S-y, S2edish, 5t h-+e9lly ndestanda5le.



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GKE ELEKTRONIK AB, GRANBERGSDAL, SWEDEN. !" #$" %&&"" GKE'SWIPNET.SE SK(PE) SKOGSG*RRA !&


Thee is als- the 0Lill8Be++e0. Ahand8held 5attey8di3en nit thatcan 5e sed t- detect EDM acti3ityin 5eain/s. A 4a/net c-nnects t-/-nd and a ca5-n elect-de is

sed t- c-ntact the sha9t. ?JFs:M?Js; is set 2ith the >n-5 and2hen theeHs n- acti3ity :LED 5lin>s2hen thee is EDM; at le3els at -a5-3e % M?Js, thee is n- is>that EDM 2ill sh-ten the 5eain/Hs

li9e.

a practical introduction to electric discharge machining, or “bearing currents” in bearings –...

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