Kool Mµ^® Cores

Affordable FeSiAl Material for Low Losses at Elevated Frequencies

Kool Mµ material’s low loss and relatively high saturation level (10,500 gauss) make it excellent for use in power factor correction circuits (PFC) as well as unidirectional drive applications such as Pulse Transformers and Flyback Transformers. The near zero magnetostriction makes Kool Mµ (sendust) ideal for eliminating audible frequency noise in In-Line Noise Filters and Inductors. View PFC Boost design example using Kool Mu.

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Key Characteristics

Composition: Al • Si • Fe
Shapes: Toroid, E, U, EQ, LP, EER, Block, Cylinder
Sizes: 4 mm to 165 mm
Permeability: 14µ, 19µ, 26µ, 40µ, 60µ, 75µ, 90µ, 125µ
Coating Color: Black

Large Kool Mu Toroids

Five large sizes have been added to the Kool Mu toroids, including the massive 165 millimeter core. Large Powder Core toroids are a cost-effective option for high current applications, such as UPS, large Power Factor Correction (PFC) chokes and inverters for renewable energy.

Kool Mu Shapes

Kool Mu Shapes (Toroids, E, U, EQ, LP, EER, Cylinders, Blocks and Round Blocks) are available in various sizes. These shapes compare favorably with gapped ferrites, powdered iron and silicon steel cores. In addition, for very large core requirements, these large shapes can be configured and bonded for a number of custom designs.

Property Curves

View Kool Mµ Material Property Curves including Normal Magnetization curves, Core Loss Density curves, Permeability versus Temperature curves, Permeability versus DC Bias curves, and Permeability versus Frequency curves.

Kool Mµ Part Number Identification

How To Order: magnetics powder cores

Kool Mµ Toroid
Kool Mµ E
Kool Mµ U
Kool Mµ EQ
Kool Mu LP
Kool Mµ EER
Kool Mµ Block
Kool Mμ Cylinder

Core Data	AL nH/T2 (nominal)								Le Path Length mm	Ae Cross Section mm2	Ve Volume mm3	OD max mm	ID min mm	HT max mm
Core Data	14µ	19µ	26µ	40µ	60µ	75µ	90µ	125µ	Le Path Length mm	Ae Cross Section mm2	Ve Volume mm3	OD max mm	ID min mm	HT max mm
140					13	16	19	26	8.06	1.30	10.5	4.19	1.27	2.16
150					17	21	25	35	9.42	2.11	19.9	4.58	1.72	3.18
180					20	25	30	42	10.6	2.85	30.3	5.29	1.85	3.18
020	6	8	10	18	24	30	36	50	13.6	4.7	64	6.99	2.29	3.43
240	6	8	11	17	26	32	39	54	13.6	4.76	64.9	7.24	2.15	3.18
270	12	16	21	33	50	62	74	103	13.6	9.2	125	7.24	2.16	5.41
410	8	11	14	22	33	41	50	70	16.5	7.25	120	7.49	3.45	5.72
030	6	8	11	17	25	31	37	52	17.9	5.99	107	8.51	3.45	3.81
280	6	8	11	17	25	32	38	53	21.8	7.52	164	10.29	4.27	3.81
290	7	10	14	22	32	41	48	66	21.8	9.45	206	10.29	4.27	4.60
040	7	10	14	21	32	40	48	66	23	9.57	220	10.80	4.57	4.60
130	6	8	11	17	26	32	38	53	26.9	9.06	244	11.81	5.84	4.60
050	6	9	12	18	27	34	40	56	31.2	10.9	340	13.46	6.99	5.51
120	8	11	15	24	35	43	52	72	41.2	19.2	791	17.27	9.53	7.11
380	10	14	19	28	43	53	64	89	41.4	23.2	960	18.03	9.02	7.11
206	7	10	14	21	32	41	49	68	50.9	22.1	1,120	21.08	12.07	7.11
310	9	14	19	29	43	54	65	90	56.7	31.7	1,800	23.62	13.34	8.38
350	12	16	22	34	51	62	76	105	58.8	38.8	2,280	24.33	13.77	9.65
930	18	23	32	50	75	94	113	157	63.5	65.4	4,150	27.69	14.10	11.94
426			30		69		104	144	66.5	72.7	4,840	30.00	17.40	10.90
548	14	20	28	41	61	76	91	127	81.4	65.6	5,340	33.66	19.46	11.43
585	9	12	16	25	38	47	57	79	89.5	46.6	4,150	35.18	22.56	9.78
324	13	18	24	37	56	70	84	117	89.8	67.8	6,090	36.70	21.54	11.35
395	28	39	53	81	122	153	183	254	95.1	153.7	14,617	40.94	21.27	17.89
254	19	26	35	54	81	101	121	168	98.4	107	10,600	40.77	23.32	15.37
395	28	39	53	81	122	153	183	254	94.0	153	14,600	40.94	21.27	17.89
454	25	34	47	72	108	135	161	224	102	147.5	15,100	43.84	23.39	17.27
089	20	27	37	57	86	107	128	178	116	134	15,600	47.63	27.89	16.13
438	32	43	59	90	135	169	202	281	107	199	21,300	47.63	23.32	18.92
725	41	56	76	117	175	219	269	366	114	262	29,700	51.51	24.00	21.59
715	17	23	32	49	73	91	109	152	127	125	15,900	51.69	30.94	14.35
540	24	33	45	69	104	130	156	217	126	174	22,000	54.90	28.10	15.30
109	18	24	33	50	75	94	112	156	143	144	20,700	58.04	34.75	14.86
195	32	44	60	92	138	172	207	287	125	229	28,600	58.04	25.58	16.13
596	29	39	54	83	125	156	187	259	143	237	33,900	60.60	33.00	20.50
620	44	60	82	126	189	237	284	394	144	360	51,800	63.09	31.70	25.91
070	35	48	65	100	143	187	225	312	158	314	49,700	69.42	34.67	21.41
778	47	64	88	135	205	256	306	425	177.2	492	81,500	78.94	38.33	26.85
740	48	64	88	136	204	255	306	425	184	497	91,400	75.21	44.40	35.92
866	16	22	30	45	68	85	102	142	196	176	34,500	78.94	48.21	13.84
906	20	27	37	57	85	106	128	177	196	221	43,400	78.94	48.21	17.02
102	26	35	48	74	111	139	167	232	243	358	86,900	103.00	55.75	17.91
337	37	50	68	105	158				324	678	220,000	133.96	77.19	26.80
165	42	57	78						412	987	407,000	166.50	101.02	33.15

Core Data	A_L nH/T² (nominal)					L_e Path Length mm	A_e Cross Section mm²	V_e Volume mm³	Length max mm	Leg Length min mm	Height max mm
Core Data	14µ	26µ	40µ	60µ	90µ	L_e Path Length mm	A_e Cross Section mm²	V_e Volume mm³	Length max mm	Leg Length min mm	Height max mm
1808		26	35	48	69	40.1	22.8	914	19.6	7.9	4.93
2510		39	52	70	100	48.5	38.5	1,867	25.8	9.4	6.45
3007		33	46	71	92	65.6	60.1	3,943	30.6	14.8	7.21
3515		56	75	102	146	69.4	84	5,830	35.1	14.0	9.53
4017		56	76	105	151	98.4	128	12,595	43.5	20.8	11.0
4020		80	108	150	217	98.4	183	18,007	43.5	20.8	15.7
4022		104	140	194	281	98.4	237	23,321	43.5	20.8	20.3
4317		88	119	163	234	77.5	152	11,800	41.5	16.2	12.7
5528		116	157	219	322	123	350	43,100	55.7	27.2	21.0
5530		138	187	261	338	123	417	51,400	55.7	27.2	25.0
6527	103	162	230	300		147	540	79,400	66.4	32.1	27.4
7228		130	173	235		137	368	50,400	73.5	27.4	19.4
8020	75	103	145	190		185	389	72,000	81.2	37.5	20.2
8024		200	275	370		131.4	600	78,840	81.2	23.4	30.1
8044		91	113	170		208	389	80,900	81.2	44.0	20.2
114LE	161	235		445		215	1220	262,000	115.1	45.8	35.3
130LE		254				219	1080	237,000	134.1	32.2	55.1
160LE		180				273	778	212,000	162.5	37.5	40.9

Core Data	AL nH/T2 (nominal)				Le Path Length mm	Ae Cross Section mm2	Ve Volume mm3	Length max mm	Leg Length min mm	Height max mm
Core Data	26µ	40µ	60µ	90µ	Le Path Length mm	Ae Cross Section mm2	Ve Volume mm3	Length max mm	Leg Length min mm	Height max mm
3112		92	111	179	65.6	101	6,620	31.8	10.9	12.5
4110			78		85.2	80	6,816	41.2	10.7	9.9
4111		72	95	138	85.2	101	8,605	41.2	10.9	12.5
4119		110	151	218	85.2	160	13,632	41.2	10.9	19.5
5527	67				168	172	28,896	55.5	27.1	16.7
5529	85				168	244	40,992	55.5	27.1	23.6
6527	89		165		219	270	59,130	66.6	32.2	27.4
6533	82				199	250	49,750	66.6	32.2	20.4
7236	87				219	290	63,510	73.3	34.9	21.3
8020	64				273	195	53,235	81	37.5	20.2
8038	97		179		237	354	83,898	81	37.5	23.4

Core Data	A_L nH/T² (nominal)				L_e Path Length mm	A_eCross Section mm²	Length mm	Height mm	Width mm
Core Data	26µ	40µ	60µ	75µ	L_e Path Length mm	A_eCross Section mm²	Length mm	Height mm	Width mm
EQK20 L050	81	120	167	203	29.3	60.8	20.0	5.0	14.0
EQK20 L061	67	98	138	166	35.8	60.8	20.0	6.1	14.0
EQK26 L070	111	164	228		42.3	119.8	26.5	7.0	19.0
EQK26 L088	95	140	195		49.5	119.8	26.5	8.8	19.0
EQK26 L101	86	127	177		54.7	119.8	26.5	10.1	19.0
EQK26 L124	74	108	151		63.9	119.8	26.5	12.4	19.0
EQK32 L101	100	148	207		59.5	152.3	32.0	10.1	22.0
EQK32 L152	75	110	156		79.9	152.3	32.0	15.2	22.0
EQK32 L180	66	97	136		91.1	152.3	32.0	18.0	22.0
EQK36 L100	109	160	223	272	65.1	180.8	36.0	10.0	26.0
EQK36 L110	102	151	211	256	69.1	180.8	36.0	11.0	26.0
EQK36 L174	75	110	154	187	94.7	180.8	36.0	17.4	26.0
EQK41 L120	94	138	193	234	83.6	199.7	41.5	12.0	28.0
EQK41 L199	68	100	140	163	115.2	199.7	41.5	19.9	28.0
EQK50 L200	109	160	223	271	113.4	314.1	50.0	20.0	32.0
EQK50 L250	92	136	190	231	133.4	314.1	50.0	25.0	32.0

Core Data	A_L nH/T² (nominal)				L_e Path Length mm	A_e Cross Section mm²	Length mm	Height mm	Width mm
Core Data	26µ	40µ	60µ	75µ	L_e Path Length mm	A_e Cross Section mm²	Length mm	Height mm	Width mm
LPK23 L087	54	79	110	134	49.1	67.0	23.4	8.7	14.0
LPK25 L099	68	100	139		55.7	96.0	25.0	9.9	18.0
LPK30 L118	65	96	134		68.0	114.0	30.0	11.8	20.0
LPK32 L152	69	101	141		82.1	143.0	32.0	15.2	22.0
LPK36 L144	86	127	177		80.6	177.0	36.2	14.4	24.0
LPK42 L107	116	171	239	290	69.7	206.0	42.0	10.7	25.0
LPK42 L123	106	156	218	265	76.1	206.0	42.0	12.3	25.0
LPK42 L158	90	132	184	224	90.1	206.0	42.0	15.8	25.0

Core Data	A_L nH/T² (nominal)			L_e Path Length mm	A_e Cross Section mm²	V_e Volume mm³	Length mm	Height mm	Width mm
Core Data	26µ	40µ	60µ	L_e Path Length mm	A_e Cross Section mm²	V_e Volume mm³	Length mm	Height mm	Width mm
ERK25 L110	34	47	65	57.8	45.0	2,600	25.5	11.0	7.5
ERK40 L224	59	81	111	111.3	149.1	16,600	40.0	22.4	13.3

Block Core Data	AL nH/T² (nominal)			Ve Volume mm³	Length mm	Width mm	Height mm	Radius mm
Block Core Data	26µ	40µ	60µ	Ve Volume mm³	Length mm	Width mm	Height mm	Radius mm
4741	PDF		PDF	53,600	47.5	41.0	27.5	N/A
5030	PDF	PDF	PDF	23,000	50.5	30.3	15.0	N/A
5241	PDF		PDF	58,700	52.0	41.0	27.5	N/A
5528	PDF	PDF	PDF	31,200	54.9	27.6	20.6	N/A
6020				56,600	60.5	20.3	20.0	N/A
6030	PDF		PDF	27,000	60.0	30.0	15.0	N/A
6131				36,700	60.5	30.3	20.0	N/A
7020	PDF	PDF	PDF	28,600	70.5	20.3	20.0	N/A
7030	PDF			42,800	70.5	30.3	20.0	N/A
8020	PDF	PDF	PDF	32,700	80.5	20.3	20.0	N/A
8030	PDF	PDF	PDF	48,800	80.5	30.3	20.0	N/A
9030				54,843	90.5	30.3	20.0	N/A
9541	PDF	PDF	PDF	107,200	95.0	41.0	27.5	N/A
Round Block Core Data
3515				12,175	35.3	15.2	25.0	7.5
6034	PDF		PDF	17,900	60.0	34.0	10.0	17.0
6524				27,000	64.5	24.2	18.8	12.0
7528				40,900	74.5	27.5	21.7	13.75
7543			PDF	43,800	75.0	43.0	15.5	21.5
8030				44,700	80.5	30.2	23.5	15.0
8430				53,500	84.0	30.0	23.0	15.0
9040				48,850	90.0	40.0	15.0	20.0

Core Data	Permeability						Width mm	Height mm
Core Data	26µ	40µ	45µ	60µ	75µ	90µ	Width mm	Height mm
00K011020CXXX	X	X		X		X	11.4	20.0
00K015010CXXX	X	X		X		X	15.0	10.5
00K015012CXXX	X	X	X	X		X	15.0	12.0
00K015018CXXX	X	X		X		X	15.0	18.0
00K015020CXXX	X	X		X		X	15.0	20.0
00K015022CXXX	X	X		X		X	15.0	22.0
00K020010CXXX	X	X		X		X	20.32	10.0
00K021020CXXX	X	X		X		X	21.0	20.0
00K024020CXXX	X	X		X		X	24.0	20.0
00K028020CXXX	X	X		X		X	27.6	20.0
00K028022CXXX	X	X		X	X	X	27.6	21.5
00K028024CXXX		X					27.6	24.0
00K030018CXXX	X	X		X	X	X	30.0	18.0
00K030020CXXX	X	X		X		X	30.0	20.0
00K030027CXXX	X	X		X	X	X	30.0	27.5
00K030030CXXX		X					30.0	30.0
00K033020CXXX	X	X		X		X	33.0	20.0
00K033022CXXX	X	X		X	X	X	33.0	21.5
00K042020CXXX	X	X		X		X	42.0	20.0
00K042030CXXX	X						42.0	30.0
00K047020CXXX	X	X		X		X	46.74	20.0
00K051020CXXX	X	X		X		X	50.55	20.0
00K057015CXXX	X	X		X		X	57.15	15.0
00K074020CXXX	X	X		X		X	74.1	20.0
00K074025CXXX	X	X		X		X	74.0	25.0
00K078030CXXX	X						77.8	30.0

Kool Mµ® Cores