Capacitors zisanzwe zigabanya ibiciro za Dc Link mu modoka zikoresha amashanyarazi - Capacitor y'amashanyarazi ikoreshwa mu kubika ingufu – CRE

Ibisobanuro bigufi:

Ibisobanuro birambuye ku gicuruzwa

Ibirango by'ibicuruzwa

Videwo bifitanye isano

Ibitekerezo (2)

Ikurikiza amahame agira ati "inyangamugayo, ikora cyane, ifite ubucuruzi, ihanga udushya" kugira ngo ibone ibisubizo bishya buri gihe. Ifata amahirwe n'intsinzi nk'intsinzi yayo bwite. Reka twubake ahazaza heza dufatanyijeUmuyoboro w'ifuru ukoresha frequency iciriritse , Umuyoboro w'amashanyarazi uhindura imiterere , Umuyoboro wa Filime ukoresha amashanyarazi menshiUbu twamaze gushyiraho umubano uhamye kandi mu gihe kirekire w’ubucuruzi n’abakiriya baturutse muri Amerika ya Ruguru, Uburayi bw’Iburengerazuba, Afurika, Amerika y’Epfo, ibihugu birenga 60 n’uturere.

Capacitors zisanzwe zigabanya ibiciro za Dc Link mu modoka zikoresha amashanyarazi - Capacitor y'amashanyarazi ikoreshwa mu kubika ingufu - CRE Ibisobanuro birambuye:

Amakuru ya tekiniki

Ingano y'ubushyuhe bwo gukora	Ubushyuhe bwo gukora cyane., Hejuru, ntarengwa: +85℃ Ubushyuhe bwo mu cyiciro cyo hejuru: + 70℃ Ubushyuhe bwo mu cyiciro kiri hasi: -40℃
urwego rw'ubushobozi	50μF～4000μF
Voltage idahari/ Ifite amanota	450V.DC～4000V.DC
Cap.tol	± 5% (J) ;± 10% (K)
Ihangane n'amashanyarazi	Vt-t	1.5Un DC/60S
	Vt-c	1000+2×Un/√2 (V.AC) 60S (min3000 V.AC)
Hejuru y'Umuvuduko w'amashanyarazi	1.1Un (30% by'igihe cyose cyo gusohora)
	1.15Un (iminota 30 ku munsi)
	1.2Un (iminota 5/umunsi)
	1.3Un (umunota 1 ku munsi)
	1.5Un (100ms buri gihe, inshuro 1000 mu gihe cy'ubuzima bwose)
Impamvu yo gusohora	tgδ≤0.003 f=100Hz
	tgδ0≤0.0002
Ubudahangarwa bw'ubwirinzi bw'ibintu bikingira	Rs*C≥10000S (kuri 20℃ 100V.DC 60s)
Kudakomeza gutwika	UL94V-0
Ubushobozi ntarengwa	metero 3500
	Iyo ubutumburuke buri hejuru ya metero 3500 kugeza muri metero 5500, ni ngombwa gusuzuma ikoreshwa ry'ingano igabanijwe. (kuri buri kwiyongera kwa metero 1000, voltage n'umuvuduko bizagabanukaho 10%).
Icyizere cy'ubuzima	100000h (Un; Θhotspot≤70 ° C)
Igipimo ngenderwaho	IEC61071 ;GB/T17702;

Ikiranga

1. Gufunga igitambaro cy'uruziga cya aluminiyumu, gusukamo resin yumye;

2. Ibyuma by'abagabo n'abagore, byoroshye kubishyiraho;

3. Ubushobozi bunini, ingano nto;

4. Kurwanya ingufu nyinshi z'amashanyarazi, hamwe no kwivura ubwabyo;

5. Umugezi ushyushye cyane, ubushobozi bwo kwihanganira dv / dt buri hejuru.

Kimwe n'ibindi bicuruzwa bya CRE, capacitor y'uruhererekane ifite icyemezo cya UL kandi yapimwe 100% by'ubushyuhe.

Porogaramu

1. Inverter ya Pv;
2. ihindura ingufu z'umuyaga;
3. Ubwoko bwose bwa frequencing na inverter;
4. Electron na charger pile;
5. Ibikoresho bya PFC, UPS, SVG, SVC;
6. ubundi bwoko bw'imicungire y'ubuziranenge bw'amashanyarazi.

Icyizere cy'ubuzima

Igishushanyo mbonera

ΦD(mm)	P(mm)	H1 (mm)	S	F	M
76	32	20	M12×16	M6×10	M8×20
86	32	20	M12×16	M6×10	M8×20
96	45	20	M12×16	M6×10	M8×20
116	50	22	M12×16	M6×10	M8×20
136	50	30	M16×25	M6×10	M8×20

Umuvuduko w'amashanyarazi	450V.DC
Cn(uF)	φD	H	ESL (nH)	dv/dt(V/μS)	Ip (KA)	Is(KA)	Irms(A)50℃	ESR (mΩ) @1KHz	Rth (K/W)	P(mm)	uburemere (Kg)
380	76	75	50	10	3.8	11.4	45	2.2	4.5	32	0.5
500	76	100	40	8	4.0	12.0	65	1.5	3.2	32	0.6
750	76	130	50	5	3.8	11.3	65	1.6	3.0	32	0.75
500	86	75	50	8	4.0	12.0	55	1.8	3.7	32	0.8
1000	86	130	50	5	5.0	15.0	70	1.5	2.7	32	1.1
650	86	100	40	5	3.3	9.8	75	1.2	3.0	32	0.9
650	86	95	40	5	3.3	9.8	75	1.2	3.0	32	0.85
650	96	75	50	5	3.3	9.8	60	1.5	3.7	45	0.75
1250	96	130	50	4	5.0	15.0	80	1	3.1	45	1.2
1800	116	130	50	4	7.2	21.6	85	0.8	3.5	50	1.6
1450	86	190	60	4	5.8	17.4	90	0.9	2.7	32	1.55
2700	116	190	60	3	8.1	24.3	100	0.8	2.5	50	2.45

Umuvuduko w'amashanyarazi	600V.DC
Cn(uF)	φD	H	ESL (nH)	dv/dt(V/μS)	Ip (KA)	Is(KA)	Irms(A)50℃	ESR (mΩ) @1KHz	Rth (K/W)	P(mm)	uburemere (Kg)
250	76	75	40	15	3.8	11.3	40	3.1	4.0	32	0.5
320	76	100	40	10	3.2	9.6	40	2.2	5.7	32	0.6
470	76	130	45	12	5.6	16.9	60	1.8	3.1	32	0.75
330	86	75	40	15	5.0	14.9	45	2.4	4.1	32	0.8
600	86	120	45	12	7.2	21.6	60	1.3	4.3	32	1.05
650	86	130	50	12	7.8	23.4	70	1.2	3.4	32	1.1
650	86	95	50	15	9.8	29.3	65	1.2	3.9	32	0.85
1000	86	180	50	12	12.0	36.0	70	1.5	2.7	32	1.5
420	96	75	45	15	6.3	18.9	50	2	4.0	45	0.75
800	96	130	60	12	9.6	28.8	75	1.5	2.4	45	1.2
950	116	100	60	10	9.5	28.5	90	1.2	2.1	50	1.25
1200	116	130	70	8	9.6	28.8	80	1.2	2.6	50	1.6
1800	116	180	50	8	14.4	43.2	80	1.2	2.6	50	2.4
2700	116	260	70	5	13.5	40.5	100	0.9	2.2	50	3.2
2500	136	180	60	5	12.5	37.5	100	0.8	2.5	50	3.7
3750	136	260	70	4	15.0	45.0	115	0.7	2.2	50	4.7

Umuvuduko w'amashanyarazi	700V.DC
Cn(uF)	φD	H	ESL (nH)	dv/dt(V/μS)	Ip (KA)	Is(KA)	Irms(A)50℃	ESR (mΩ) @1KHz	Rth (K/W)	P(mm)	uburemere
200	76	75	40	15	3.0	9.0	40	4	3.1	32	0.5
400	76	130	45	15	6.0	18.0	60	2	2.8	32	0.75
420	76	130	50	15	6.3	18.9	60	2	2.8	32	0.75
600	86	125	60	15	9.0	27.0	45	3.2	3.1	32	1.05
550	86	130	50	12	6.6	19.8	65	1.8	2.6	32	1.1
680	96	130	45	12	8.2	24.5	75	1.5	2.4	45	1.2
720	96	125	60	12	8.6	25.9	55	2.6	2.5	45	1.15
1000	116	130	50	10	10.0	30.0	80	1	3.1	50	1.6
1000	96	180	60	10	10.0	30.0	75	1.2	3.0	45	1.6
1500	116	180	60	7	10.5	31.5	85	0.9	3.1	50	2.4
2000	116	230	70	7	14.0	42.0	85	0.8	3.5	50	3
2000	136	180	60	7	14.0	42.0	90	0.75	3.3	50	3.7
3000	136	230	70	5	15.0	45.0	100	0.7	2.9	50	4.2
3300	136	260	70	5	16.5	49.5	120	0.6	2.3	50	4.7

Umuvuduko w'amashanyarazi	800V.DC
Cn(uF)	φD	H	ESL (nH)	dv/dt(V/μS)	Ip (KA)	Is(KA)	Irms(A)50℃	ESR (mΩ) @1KHz	Rth (K/W)	P(mm)	uburemere (Kg)
110	86	80	45	20	2.2	6.6	75	2	1.8	32	0.8
150	86	95	45	20	3.0	9.0	80	1.5	2.1	32	0.85
250	86	75	45	15	3.8	11.3	45	3.1	3.2	32	0.8
360	86	130	55	12	4.3	13.0	65	2.2	2.2	32	1.1
470	86	130	45	12	5.6	16.9	70	2.8	1.5	32	1.1
600	96	130	55	10	6.0	18.0	75	2.2	1.6	45	1.2
730	86	180	55	10	7.3	21.9	70	1.8	2.3	32	1.5
750	86	180	55	12	9.0	27.0	75	1.8	2.0	32	1.5
1000	96	180	60	10	10.0	30.0	75	1.3	2.7	45	1.6
900	116	130	65	7	6.3	18.9	80	1.4	2.2	50	1.6
1400	116	180	65	7	9.8	29.4	80	0.9	3.5	50	2.4
1000	116	125	60	7	7.0	21.0	70	1.4	2.9	50	1.55
2000	116	230	65	5	10.0	30.0	85	0.9	3.1	50	3
2800	136	230	70	5	14.0	42.0	100	0.8	2.5	50	4.2

Umuvuduko w'amashanyarazi	900V.DC
Cn(uF)	φD	H	ESL (nH)	dv/dt(V/μS)	Ip (KA)	Is(KA)	Irms(A)50℃	ESR (mΩ) @1KHz	Rth (K/W)	P(mm)	uburemere (Kg)
160	76	75	40	15	3.0	9.0	35	3	5.4	32	0.5
320	76	130	50	15	5.0	14.9	60	3.2	1.7	32	0.75
350	76	125	50	15	5.0	15.0	40	2.8	4.5	32	0.75
210	86	75	40	15	3.2	9.5	40	2.2	5.7	32	0.8
450	86	125	45	12	5.4	16.2	50	2.7	3.0	32	1.1
420	86	130	45	12	5.0	15.1	65	2.5	1.9	32	1.1
490	86	120	45	10	4.9	14.7	70	1.8	2.3	32	1.05
510	86	120	45	10	5.1	15.3	70	1.8	2.3	32	1.05
660	86	180	50	10	6.6	19.8	70	2	2.0	32	1.5
900	86	230	50	10	9.0	27.0	65	2.1	2.3	32	1.8
580	96	125	50	10	5.8	17.4	55	3.3	2.0	45	1.2
540	96	130	50	7	3.8	11.3	75	1.5	2.4	45	1.2
630	116	100	55	7	4.4	13.2	60	2	2.8	50	1.3
860	116	125	55	7	6.0	18.1	60	2.2	2.5	50	1.55
810	116	130	60	7	5.7	17.0	80	1.2	2.6	50	1.6
1250	116	180	60	7	8.8	26.3	80	1.2	2.6	50	2.4
1700	116	230	60	5	8.5	25.5	80	1.1	2.8	50	3
1700	136	180	65	6	10.2	30.6	100	0.9	2.2	50	3.7
2400	136	230	70	5	12.0	36.0	100	0.95	2.1	50	4.2

Umuvuduko w'amashanyarazi	1100V.DC
Cn(uF)	φD	H	ESL (nH)	dv/dt(V/μS)	Ip (KA)	Is(KA)	Irms(A)50℃	ESR (mΩ) @1KHz	Rth (K/W)	P(mm)	uburemere
130	76	75	40	15	1.9	5.6	35	4.5	3.6	32	0.5
260	76	130	45	15	3.8	11.3	60	2.8	2.0	32	0.75
280	76	125	50	12	3.3	9.9	35	4	4.1	32	0.75
170	86	75	50	15	2.6	7.7	45	5	2.0	32	0.8
360	86	125	55	12	4.3	13.0	35	2.5	6.5	32	1.1
330	86	130	45	15	5.0	15.0	65	2.8	1.7	32	1.1
420	86	136	45	12	5.0	15.0	60	2	2.8	32	1.15
420	86	155	45	12	5.0	15.0	65	1.5	3.2	32	1.25
470	86	180	60	10	4.7	14.1	70	1.8	2.3	32	1.5
500	86	180	60	10	5.0	15.0	70	1.8	2.3	32	1.5
600	86	225	60	10	6.0	18.0	80	1.2	2.6	32	1.8
600	86	225	70	10	6.0	18.0	60	2.2	2.5	32	1.8
600	116	130	50	10	6.0	18.0	75	1.8	2.0	50	1.6
680	86	225	70	12	8.2	24.5	65	2.5	1.9	32	1.8
720	86	230	70	12	8.6	25.9	65	2.5	1.9	32	1.8
460	96	125	65	10	4.6	13.8	55	3.2	2.1	45	1.2
520	96	180	65	12	6.2	18.7	75	1.5	2.4	45	1.6
500	116	100	70	10	5.0	15.0	55	2.5	2.6	50	1.3
680	116	125	70	10	6.8	20.4	60	2.8	2.0	50	1.6
650	116	130	75	10	6.5	19.5	75	1.3	2.7	50	1.6
1000	116	180	75	12	12.0	36.0	75	1.5	2.4	50	2.4
1200	116	230	80	8	9.6	28.8	80	1.5	2.1	50	3
1200	116	230	75	12	14.4	43.2	105	0.9	2.0	50	3
1250	116	230	75	12	15.0	45.0	80	1.5	2.1	50	3
1300	116	230	75	12	15.6	46.8	80	1.5	2.1	50	3
1400	136	180	70	7	9.8	29.4	85	1.3	2.1	50	3.7
1700	136	230	70	5	8.5	25.5	100	1.4	1.4	50	4.2
1900	136	230	75	5	9.5	28.5	100	1.2	1.7	50	4.2
2800	136	335	80	5	14.0	42.0	120	0.8	1.7	50	6.1
3060	136	345	80	5	15.3	45.9	120	0.9	1.5	50	6.2
3200	136	335	80	5	16.0	48.0	120	0.85	1.6	50	6.1

Umuvuduko w'amashanyarazi	1200V.DC
Cn(uF)	φD	H	ESL (nH)	dv/dt(V/μS)	Ip (KA)	Is(KA)	Irms(A)50℃	ESR (mΩ) @1KHz	Rth (K/W)	P(mm)	uburemere (Kg)
170	86	75	50	15	2.6	7.7	45	4.5	2.2	32	0.8
420	76	145	50	15	6.3	18.9	30	12	1.9	32	0.85
330	86	130	45	15	5.0	15.0	65	2.8	1.7	32	1.1
420	86	136	45	12	5.0	15.0	65	2	2.4	32	1.15
420	86	155	45	12	5.0	15.0	70	1.5	2.7	32	1.25
420	116	95	55	10	4.2	12.6	80	1.4	2.2	50	1.2
450	86	160	55	12	5.4	16.2	70	2.9	1.4	32	1.3
470	86	180	60	12	5.6	16.9	70	2.8	1.5	32	1.5
470	86	225	60	12	5.6	16.9	70	2.8	1.5	32	1.8
550	86	145	55	12	6.6	19.8	40	11	1.1	32	1,2
600	86	225	60	10	6.0	18.0	80	1.2	2.6	32	1.8
600	86	225	70	10	6.0	18.0	60	2.2	2.5	32	1.8
600	116	130	50	10	6.0	18.0	75	1.8	2.0	50	1.6
680	86	225	70	12	8.2	24.5	65	2.5	1.9	32	1.8
500	116	100	65	10	5.0	15.0	55	2.6	2.5	50	1.2
680	116	125	65	10	6.8	20.4	50	2.8	2.9	50	1.55
650	116	130	65	10	6.5	19.5	80	1.8	1.7	50	1.6
1000	116	180	70	7	7.0	21.0	75	1.3	2.7	50	2.4
1200	116	230	70	7	8.4	25.2	75	1.3	2.7	50	3
1250	116	230	70	7	8.8	26.3	75	1.2	3.0	50	3
1400	136	180	75	7	9.8	29.4	85	1.1	2.5	50	3.7
1700	136	230	80	5	8.5	25.5	85	1	2.8	50	4.2
850	136	125	70	8	6.8	20.4	75	1.6	2.2	50	1.9
950	136	125	60	8	7.6	22.8	80	1.1	2.8	50	2.4
1200	116	180	80	8	9.6	28.8	80	1	3.1	50	2.4
1200	116	180	60	5	6.0	18.0	100	0.8	2.5	50	2.4
1500	136	180	70	5	7.5	22.5	100	0.9	2.2	50	3.7
2700	136	335	80	5	13.5	40.5	110	0.85	1.9	50	6.1

Umuvuduko w'amashanyarazi	1300V.DC
Cn(uF)	φD	H	ESL (nH)	dv/dt(V/μS)	Ip (KA)	Is(KA)	Irms(A)50℃	ESR (mΩ) @1KHz	Rth (K/W)	P(mm)	uburemere
230	86	125	50	15	5.7	17.1	35	5	3.3	32	1.1
210	86	130	50	15	3.2	9.5	70	2	2.0	32	1.1
330	86	180	60	15	5.0	14.9	65	3	1.6	32	1.5
470	86	230	65	12	5.6	16.9	65	3.2	1.5	32	1.8
410	116	130	65	12	4.9	14.8	80	1.8	1.7	50	1.6
650	116	180	65	10	6.5	19.5	85	2	1.4	50	2.4
880	116	230	80	10	8.8	26.4	85	2.2	1.3	50	3
900	136	180	70	7	6.3	18.9	100	1.6	1.3	50	3.7
1200	136	230	80	7	8.4	25.2	105	1.5	1.2	50	4.2

Umuvuduko w'amashanyarazi	1500V.DC
Cn(uF)	φD	H	ESL (nH)	dv/dt(V/μS)	Ip (KA)	Is(KA)	Irms(A)50℃	ESR (mΩ) @1KHz	Rth (K/W)	P(mm)	uburemere
160	86	125	50	15	5.7	17.1	35	5	3.3	32	1.1
160	86	130	50	15	2.4	7.2	60	3.5	1.6	32	1.1
240	86	180	55	15	3.6	10.8	65	5	0.9	32	1.5
320	86	230	55	12	3.8	11.5	60	3.5	1.6	32	1.8
300	116	130	55	12	3.6	10.8	75	2	1.8	50	1.6
470	116	180	60	10	4.7	14.1	75	2.8	1.3	50	2.4
650	116	230	60	10	6.5	19.5	80	2.8	1.1	50	3
660	136	180	60	7	4.6	13.9	100	1.8	1.1	50	3.7
900	136	230	60	6	5.4	16.2	105	1.2	1.5	50	4.2
1000	136	260	70	5	5.0	15.0	120	0.9	1.5	50	4.7

Umuvuduko w'amashanyarazi	1800V.DC
Cn(uF)	φD	H	ESL (nH)	dv/dt(V/μS)	Ip (KA)	Is(KA)	Irms(A)50℃	ESR (mΩ) @1KHz	Rth (K/W)	P(mm)	uburemere
130	86	125	55	15	5.7	17.1	35	5	3.3	32	1.1
120	86	130	55	15	1.8	5.4	60	2.5	2.2	32	1.1
180	86	180	60	15	2.7	8.1	65	2	2.4	32	1.5
260	86	230	60	12	3.1	9.4	60	3	1.9	32	1.8
230	116	130	60	12	2.8	8.3	80	2	1.6	50	1.6
360	116	180	65	10	3.6	10.8	80	3.2	1.0	50	2.4
500	116	230	70	10	5.0	15.0	75	3	1.2	50	3
510	136	180	70	7	3.6	10.7	100	2	1.0	50	3.7
680	136	230	70	7	4.8	14.3	95	2	1.1	50	4.2

Umuvuduko w'amashanyarazi	2000V.DC
Cn(uF)	φD	H	ESL (nH)	dv/dt(V/μS)	Ip (KA)	Is(KA)	Irms(A)50℃	ESR (mΩ) @1KHz	Rth (K/W)	P(mm)	uburemere
100	86	125	55	15	1.5	4.5	35	3.8	4.3	32	1.1
90	86	130	55	15	1.4	4.1	65	2.5	1.9	32	1.1
150	86	180	60	15	2.3	6.8	60	3.5	1.6	32	1.5
200	86	230	60	12	2.4	7.2	65	2	2.4	32	1.8
180	116	130	65	10	1.8	5.4	75	2.5	1.4	50	1.6
280	116	180	70	10	2.8	8.4	70	2	2.0	50	2.4
380	116	230	80	10	3.8	11.4	80	2	1.6	50	3
400	136	180	60	7	2.8	8.4	100	1.6	1.3	50	3.7
550	136	230	70	7	3.9	11.6	100	1.5	1.3	50	4.2
850	136	335	80	5	4.3	12.8	120	1.1	1.3	50	6.1

Umuvuduko w'amashanyarazi	2800V.DC
Cn(uF)	φD	H	ESL (nH)	dv/dt(V/μS)	Ip (KA)	Is(KA)	Irms(A)50℃	ESR (mΩ) @1KHz	Rth (K/W)	P(mm)	uburemere
160	116	180	70	30	4.8	14.4	75	2.2	1.6	50	2.4
210	116	230	75	25	5.3	15.8	70	2.8	1.5	50	3
225	136	180	75	20	4.5	13.5	85	2	1.4	50	3.7
300	136	230	80	15	4.5	13.5	80	2.5	1.3	50	4.2

Umuvuduko w'amashanyarazi	4000V.DC
Cn(uF)	φD	H	ESL (nH)	dv/dt(V/μS)	Ip (KA)	Is(KA)	Irms(A)50℃	ESR (mΩ) @1KHz	Rth (K/W)	P(mm)	uburemere
70	116	180	70	50	3.5	10.5	70	3.5	1.2	50	2.4
95	116	230	75	40	3.8	11.4	70	3.6	1.1	50	3
100	136	180	75	35	3.5	10.5	85	3	0.9	50	3.7
135	136	230	80	30	4.1	12.2	80	3.5	0.9	50	4.2

Amafoto arambuye y'ibicuruzwa:

Ubuyobozi bw'ibicuruzwa bifitanye isano:

Ubusanzwe dutekereza kandi tugakoresha uburyo bujyanye n'impinduka z'imimerere, kandi tugakura. Tugamije kugera ku bushobozi bwo kugira ubwenge n'umubiri mwiza ndetse no kubaho ku bikoresho bisanzwe bigabanya ibiciro bya Dc Link Capacitors mu modoka zikoresha amashanyarazi - Capacitor y'amashanyarazi ikoreshwa mu kubika ingufu - CRE, Iki gicuruzwa kizagezwa ku isi yose, nka: Toronto, Koreya, Chypre, Mu rwego rwo gukoresha amakuru n'ibindi byinshi mu bucuruzi mpuzamahanga, twishimiye abaguzi baturutse hirya no hino kuri interineti no hanze ya interineti. Nubwo hari ibicuruzwa n'ibisubizo byiza dutanga, serivisi nziza kandi ishimishije itangwa n'itsinda ryacu ry'abakora nyuma yo kugurisha. Urutonde rw'ibisubizo n'ibipimo birambuye n'andi makuru yose bizoherezwa ku gihe kugira ngo ubaze ibibazo. Rero menya neza ko watwandikira utwoherereza ama-imeyili cyangwa uduhamagare niba ufite ikibazo ku kigo cyacu. Ushobora kandi kubona amakuru y'aderesi yacu ku rubuga rwacu no kuza ku kigo cyacu, cyangwa ukareba ibisubizo byacu. Twizeye ko tugiye gusangira ibisubizo no kubaka ubufatanye bukomeye n'abagenzi bacu muri iri soko. Dutegereje ibibazo byanyu.

(Ububiko bw'ingufu nyinshi bukoreshwa amasaha menshi hakoreshejwe capacitors

Umuyoboro w'amashanyarazi wa Ac