0.75kw 1.1kw 2.2kw 3kw Ybx3 High Efficiency Three Phase Induction Electric Motor

• Customization: Available
• Application: Industrial, Universal, Household Appliances, Power Tools
• Operating Speed: Constant Speed
• Model NO.: YBX3-100L
• Species: Explosion-Proof Three-Phase
• Rotor Structure: Winding Type
• Casing Protection: Explosion-Proof Type
• Number of Poles: 2/4/6/8/10
• Starting Mode: Auto-induction Voltage-reduced Starting
• Certification: ISO9001, CCC, CE
• Kw: 3kw
• Eff: 87.1%
• Current: 6.02/3.46A
• Power Factor: 0.87
• Transport Package: Wooden Packing
• Specification: IEC60034-1. CCC
• Trademark: XINNUO
• Origin: China
• HS Code: 8501
• Production Capacity: 300PCS Per Day
• Package Size: 52.00cm * 29.00cm * 24.00cm
• Package Gross Weight: 38.000kg

Product Description

 

Workshop

Product Parameters

 

Type No.	Rated output	Speed	Electric current	EFF	Power factor	Locked current	Locked torque	Max torque
						Rated current	Rated torque	Rated torque
	kW	r/min	ln(A)	n(%)	Cos	lst/ln	Tst/TN	Tmax/TN
synhronous speed 3000r/min
YBX3-63M1-2	0.18	2720	0.53/0.30	65.0	0.80	5.5	2.3	2.2
YBX3-63M2-2	0.25	2720	0.69/0.40	68.0	0.81	5.5	2.3	2.2
YBX3-71M1-2	0.37	2730	1.01/0.58	69.0	0.81	6.1	2.3	2.2
YBX3-71M2-2	0.55	2730	1.38/0.79	74.0	0.82	6.1	2.3	2.3
YBX3-80M1-2	0.75	2840	1.70/0.98	80.7	0.83	6.8	2.3	2.3
YBX3-80M2-2	1.1	2840	2.43/1.40	82.7	0.83	7.3	2.3	2.3
YBX3-90S-2	1.5	2850	3.22/1.86	84.2	0.84	7.6	2.3	2.3
YBX3-90L-2	2.2	2850	4.58/2.64	85.9	0.85	7.8	2.3	2.3
YBX3-100L-2	3	2870	6.02/3.46	87.1	0.87	8.1	2.3	2.3
YBX3-112M-2	4	2890	7.8/4.5	88.1	0.88	8.3	2.3	2.3
YBX3-132S1-2	5.5	2900	10.7/6.1	89.2	0.88	8.0	2.2	2.3
YBX3-132S2-2	7.5	2900	14.2/8.2	90.1	0.89	7.8	2.2	2.3
YBX3-160M1-2	11	2930	20.6/11.9	91.2	0.89	7.9	2.2	2.3
YBX3-160M2-2	15	2930	27.9/16.0	91.9	0.89	8.0	2.2	2.3
YBX3-160L-2	18.5	2930	34.1/19.7	92.4	0.89	8.1	2.2	2.3
YBX3-180M-2	22	2950	40.5/23.3	92.7	0.89	8.2	2.2	2.3
YBX3-200L1-2	30	2950	54.9//31.6	93.3	0.89	7.5	2.2	2.3
YBX3-200L2-2	37	2950	67.4/38.8	93.7	0.89	7.5	2.2	2.3
YBX3-225M-2	45	2960	81.7/47.1	94.0	0.89	7.6	2.2	2.3
YBX3-250M-2	55	2960	99.6/57.3	94.3	0.89	7.6	2.2	2.3
YBX3-280S-2	75	2970	135.2/77.8	94.7	0.89	6.9	2.0	2.3
YBX3-280M-2	90	2970	161.7/93.1	95.0	0.89	7.0	2.0	2.3
YBX3-315S-2	110	2980	197.3/113.6	95.2	0.89	7.1	1.9	2.2
YBX3-315M-2	132	2980	236.2/136.0	95.4	0.89	7.1	1.9	2.2
YBX3-315L1-2	160	2980	285.7/164.5	95.6	0.89	7.1	1.9	2.2
YBX3-315L2-2	200	2980	356.4/205.2	95.8	0.89	7.1	1.9	2.2
YBX3-355S1-2	185	2980	330.3/190.2	95.6	0.89	7.1	1.9	2.2
YBX3-355S2-2	200	2980	356.4/205.2	95.8	0.89	7.1	1.9	2.2
YBX3-355M1-2	220	2980	392.0/225.7	95.8	0.89	7.1	1.8	2.2
YBX3-355M2-2	250	2980	440.5/253.7	95.8	0.90	7.1	1.8	2.2
YBX3-355L1-2	280	2980	493.4/284.1	95.8	0.90	7.1	1.8	2.2
YBX3-355L2-2	315	2980	555.1/319.6	95.8	0.90	7.1	1.8	2.2
synhronous speed 1500r/min
YBX3-63M1-4	0.12	1340	0.44/0.26	57.0	0.72	4.4	2.3	2.2
YBX3-63M2-4	0.18	1340	0.62/0.36	60.0	0.73	4.4	2.3	2.2
YBX3-71M1-4	0.25	1350	0.79/0.45	65.0	0.74	5.2	2.3	2.2
YBX3-71 M2-4	0.37	1350	1.12/0.64	67.0	0.75	5.2	2.3	2.2
YBX3-80M1-4	0.55	1390	1.43/0.82	77.8	0.75	6.3	2.3	2.3
YBX3-80M2-4	0.75	1390	1.84/1.06	82.5	0.75	6.5	2.3	2.3
YBX3-90S-4	1.1	1400	2.65/1.53	84.1	075	6.6	2.3	2.3
YBX3-90L-4	1.5	1400	3.56/2.05	85.3	0.75	6.9	2.3	2.3
YBX3-100L1-4	2.2	1420	4.76/2.74	86.7	0.81	7.5	2.3	2.3
YBX3-100L2-4	3	1420	6.34/3.65	87.7	0.82	7.6	2.3	2.3
YBX3-112M-4	4	1430	8.4/4.8	88.6	0.82	7.7	2.3	2.3
YBX3-132S-4	5.5	1450	11.4/6.6	89.6	0.82	7.5	2.0	2.3
YBX3-132M-4	7.5	1450	15.2/8.7	90.4	0.83	7.4	2.0	2.3
YBX3-160M-4	11	1450	21.5/12.4	91.4	0.85	7.5	2.0	2.3
YBX3-160L-4	15	1450	29.1/16.8	92.1	0.85	7.5	2.0	2.3
YBX3-180M-4	18.5	1470	35.3/20.3	92.6	0.86	7.7	2.0	2.3

  
 

Type No.	Rated output	Speed	Electric current	EFF	Power factor	Locked current	Locked torque	Max torque
						Rated current	Rated torque	Rated torque
	kW	r/min	ln(A)	n(%)	Cos	lst/ln	Tst/TN	Tmax/TN
synhronous speed 1500r/min
YBX3-180L-4	22	1470	41.8/24.1	93.0	0.86	7.8	2.0	2.3
YBX3-200L-4	30	1470	55.9/32.2	93.6	0.87	7.2	2.0	2.3
YBX3-225S-4	37	1480	68.8/39.6	93.9	0.87	7.3	2.0	2.3
YBX3-225M-4	45	1480	83.4/48.0	94.2	0.87	7.4	2.0	2.3
YBX3-250M-4	55	1480	100.4/57.8	94.6	0.88	7.4	2.0	2.3
YBX3-280S-4	75	1480	136.3/78.5	95.0	0.88	6.7	2.0	2.3
YBX3-280M-4	90	1480	161.4/92.9	95.2	0.89	7.0	2.0	2.3
YBX3-315S-4	110	1485	196.8/133.3	95.4	0.89	7.0	2.0	2.2
YBX3-315M-4	132	1485	235.7/135.7	95.8	0.89	7.0	2.0	2.2
YBX3-315L1-4	160	1485	285.1/164.1	96.0	0.89	7.0	2.0	2.2
YBX3-315L2-4	200	1485	355.7/204.8	95.8	0.89	7.0	2.0	2.2
YBX3-355S1 -4	185	1485	329.7/189.8	96.0	0.89	7.0	2.0	2.2
YBX3-355S2-4	200	1485	355.6/204.8	96.0	0.89	7.0	2.0	2.2
YBX3-355M1-4	220	1485	391.2/225.2	96.0	0.89	7.0	2.0	2.2
YBX3-355M2-4	250	1485	444.6/256.0	96.0	0.89	7.0	2.0	2.2
YBX3-355L1-4	280	1485	497.9/286.7	96.0	0.89	7.0	2.0	2.2
YBX3-355L2-4	215	1485	560.0/322.5	96.0	0.89	7.0	2.0	2.2
synhronous speed 1000r/min
YBX3-71M1-6	0.18	880	0.74/0.43	56.0	0.66	4.0	1.9	2.0
YBX3-71M2-6	0.25	880	0.95/0.55	59.0	0.68	4.0	1.9	2.0
YBX3-80M1-6	0.37	890	1.30/0.75	62.0	0.70	4.7	1.9	2.0
YBX3-80M2-6	0.55	890	1.58/0.91	73.6	0.72	4.7	1.9	2.1
YBX3-90S-6	0.75	910	2.01/1.15	78.9	0.72	5.8	2.1	2.1
YBX3-90L-6	1.1	910	2.83/1.63	81.0	0.73	5.9	2.1	2.1
YBX3-100L-6	1.5	930	3.73/2.15	82.5	0.74	6.0	2.1	2.1
YBX3-112M-6	2.2	940	5.36/3.09	84.3	0.74	6.0	2.1	2.1
YBX3-132S-6	3	960	7.20/4.14	85.6	0.74	6.2	2.0	2.1
YBX3-132M1-6	4	960	9.5/5.5	86.8	0.74	6.8	2.0	2.1
YBX3-132M2-6	5.5	960	12.7/7.3	88.0	0.75	7.1	2.0	2.1
YBX3-160M-6	7.5	970	16.4/9.4	89.1	0.78	6.7	2.1	2.1
YBX3-160L-6	11	970	23.7/13.7	90.3	0.78	6.9	2.1	2.1
YBX3-180L-6	15	980	30.9/17.8	91.2	0.81	7.2	2.0	2.1
YBX3-200L1-6	18.5	980	37.8/21.8	91.7	0.81	7.2	2.1	2.1
YBX3-200L2-6	22	980	44.2/25.5	92.2	0.82	7.3	2.1	2.1
YBX3-225M-6	30	980	60.6/34.9	92.9	0.81	7.1	2.0	2.1
YBX3-250M-6	37	980	71.7/41.3	93.3	0.84	7.1	2.1	2.1
YBX3-280S-6	45	980	84.9/48.9	93.7	0.86	7.2	2.1	2.0
YBX3-280M-6	55	990	103.3/59.5	94.1	0.86	7.2	2.1	2.0
YBX3-315S-6	75	990	141.7/81.6	94.6	0.85	7.0	2.0	2.0
YBX3-315M-6	90	990	171.6/98.8	94.9	0.84	7.0	2.0	2.0
YBX3-315L1-6	110	990	206.8/119.0	95.1	0.85	7.0	2.0	2.0
YBX3-315L2-6	132	990	244.5/140.7	95.4	0.86	7.0	2.0	2.0
YBX3-355S-6	160	990	292.3/168.3	95.6	0.87	7.0	1.9	2.0
YBX3-355M1-6	185	990	338.0/194.6	95.6	0.87	7.0	1.9	2.0
YBX3-355M2-6	200	990	364.6/210.0	95.8	0.87	7.0	1.9	2.0
YBX3-355L1-6	220	990	401.0/231.0	95.8	0.87	7.0	1.9	2.0
YBX3-355L2-6	250	990	455.7/262.4	95.8	0.87	7.0	1.9	2.0

  

 

	Rated		Electric	ccc	Power	Locked current	Locted torque	Max torque
Type No.	output	Speed	current	err	factor	Rated current	Rated torque	Rated toque
	kW	r/min	ln(A)	n(%)	Cos 6	lst/ln	Tst/TN	Tmax/TN

synhronous speed 750r/min

YBX3-80M1-8	0.18	630	0.88/0.51	51.0	0.61	3.3	1.8	1.9
YBX3-80M2-8	0.25	650	1J 5/0.66	54.0	0.61	33	1.8	1.9
YBX3-90S-8	0.37	670	1.49/0.86	62.0	0.61	4.0	1.8	1.9
YBX3-90L-8	0.55	670	2.17/125	63.0	0.61	4.0	1.8	2.0
YBX3-100L1-8	0.75	690	2.48/1.43	68.7	0.67	4.0	1.8	2.0
YBX3-100L2-8	1.1	690	3.53/2.03	70.7	0.67	5.0	1.8	2.0
YBX3-112M-8	1.5	690	4.41/2.54	72.8	0.71	5.0	1.8	2.0
YBX3-132S-8	22	710	6.04/3.48	77.9	0.71	6.0	1.8	2.0
YBX3-132M-8	3	710	7.91/4.56	78.9	0.73	6.0	1.8	2.0
YBX3-160M1-8	4	720	10.4/6.0	79.9	0.73	6.0	1.9	2.0
YBX3-160M2-8	5.5	720	13.8/80	82.0	0,74	6.0	1,9	2.0
YBX3-160L-8	7.5	720	18.1/10.4	84.0	0.75	6.0	1.9	2.0
YBX3-180L-8	11	720	25.8/14.9	86.4	0.75	6.5	2.0	2.0
YBX3-200L-8	15	730	34.5/19.9	86.9	0.76	6.6	2.0	2.0
YBX3-2225S-8	18.5	740	41.5/23.9	89.1	0.76	6.6	1.9	2.0
YBX3-225M-8	22	740	47.8/27.5	89.6	0.78	6.6	1.9	2.0
YBX3-250M-8	30	740	63.8/36.8	90.4	0.79	6.5	1.9	2.0
YBX3-280S-8	37	740	78.3/45.1	90.9	0.79	6.6	1.9	2.0
YBX3-280M-8	45	740	94.7/54.5	91.4	0.79	6.6	1.9	2.0
YBX3-315S-8	55	740	113.2/65.2	923	0.8	6.6	1.8	2.0
YBX3-315M-8	75	740	152.8/88.0	93.2	0.8	6.4	1.8	2.0
YBX3-315L1-8	90	740	182.8/1053	93.5	0,8	6.4	1.8	2.0
YBX3-315L2-8	110	740	218.0/125.5	93.5	0.82	6.4	1.8	2.0
YBX3-355S-8	132	740	260,7/150.1	93.8	0.82	6.4	1.8	2.0
YBX3-355M-8	160	740	315.4/181.6	94.0	0.82	6.4	1.8	2.0
YBX3-355L1-8	185	740	364.7/210.0	94.0	0.82	6.4	1.8	2.0
YBX3-355L2-8	200	740	388.7/233.8	94.2	0.83	6.4	1.8	2.0
synhronous speed 600r/min
YBX3-315S-10	45	590	99.9/57.6	91.2	0.75	6.2	1.3	2.0
YBX3-315M-10	55	590	121.4/69.9	91.8	0.75	6.2	1.3	2.0
YBX3-315L1-10	75	590	162.4/93.5	923	0.76	6.2	1.3	2.0
YBX3-315L2-10	90	590	1912/110.1	92.9	0.77	6.2	1.3	2.0
YBX3-355S-10	90	590	191.2/110.1	92.9	0.77	6.2	1.3	2.0
YBX3-355M1-10	110	590	230.2/132.5	93.1	0.78	6.0	1.3	2.0
YBX3-355M2-10	132	590	275.0/158.3	93.5	078	6.0	13	2.0
YBX3-355L1-10	160	590	333.3/191.9	93.5	0.78	6.0	1.3	2.0
YBX3-355L2-10	185	590	385.4/221.9	93.5	0.78	6.0	1.3	2.0

 

()																		:mm
Frame	Flange size	Poles						Mounting Dimension										Figure size I
			A		c	D	E	F		H		M	r		R^d	s^b		Ab.	Ac,	Ad.	H
63M	FT75	2.4	100	80	40	11	23	4	8.5	63	7	75	60	90	0	M5	4	130	150	165	230	270
71M	FT85	2.4.6	112	90	45	14	30	5	11	71	7	85	70	105	0	M6	4	140	155	165	250	300
80M	FT100	246.8	125	100	50	19	40	6	15.5	80	10	100	80	120	0	M6	4	165	165	180	320	330
90S	FT115	2.46.8	140	100	56	24	50	8	20	90	10	115	95	140	0	M8	4	180	180	180	350	380
90L	FT115	246.8	140	125	56	24	50	8	20	90	10	115	95	140	0	M8	4	180	180	180	350	410
100L	FT130	2A6.8	160	140	63	28	60	8	24	100	12	130	110	160	0	M8	4	200	205	180	400	473
112M	FT130	246.8	190	140	70	28	60	8	24	112	12	130	110	160	0	M8	4	245	230	200	420	520

											:mm
Frame	Poles			Mounting Dimension								Figure size			I
	W	A	B	C	D	E	F	G^a	H		Ab^c	Ac^1	Ad^c	Hd^c	rn
63M	2.4	100	80	40	11	23	4	8.5	63	7	130	150	165	230	270
71M	2.4.6	112	90	45	14	30	5	11	71	7	140	155	165	250	300
80M	24.6.8	125	100	50	19	40	6	15.5	80	10	165	165	180	320	330
90S	246.8	140	100	56	24	50	8	20	90	10	180	180	180	350	380
90L	2.4.6.8	140	125	56	24	50	8	20	90	10	180	180	180	350	410
100L	246.8	160	140	63	28	60	8	24	100	12	200	205	180	400	473
112M	246,8	190	140	70	28	60	8	24	112	12	245	230	200	420	520
132S	246.8	216	140	89	38	80	10	33	132	12	280	270	200	450	570
132M	24.6.8	216	178	89	38	80	10	33	132	12	280	270	200	450	615
160M	2.4.6.8	254	210	108	42	110	12	37	160	14.5	330	325	220	520	755
160L	2.4.6.S	254	254	108	42	110	12	37	160	14.5	330	325	220	520	795
180M	24.6.8	279	241	121	48	110	14	42.5	180	14.5	355	360	220	550	806
180L	246.8	279	279	121	48	110	14	42.5	180	14.5	355	360	220	550	806
200L	24.6.8	318	305	133	55	110	16	49	200	18.5	390	400	250	645	865
225S	4.8	356	286	149	60	140	18	53	225	18.5	435	450	250	690	913
225M	2	356	311	149	55	110	16	49	225	18.5	435	450	250	690	923
	4.6.8	356	311	149	60	140	18	53	225	18.5	435	450	250	690	953
250M	2	406	349	168	60	140	18	53	250	24	490	500	300	730	995
	46.8	406	349	168	65	140	18	58	250	24	490	500	300	730	995
	2	457	368	190	65	140	18	58	280	24	545	560	300	810	1047
	4.6.8	457	368	190	75	140	20	67.5	280	24	545	560	300	810	1047
280M	2	457	419	190	65	140	18	58	280	24	545	560	300	810	1122
	4.6.8	457	419	190	75	140	20	67.5	280	24	545	560	300	810	1122
	2	508	406	216	65	140	18	58	315	28	640	630	400	1020	1185
3 I 3^	4.6.8.10	508	406	216	80	170	22	71	315	28	640	630	400	1020	1260
315M	2	508	457	216	65	140	18	58	315	28	640	630	400	1020	1305
	4.6.8.10	508	457	216	80	170	22	71	315	28	640	630	400	1020	1380
	2	508	508	216	65	140	18	58	315	28	640	630	400	1020	1305
	4.6.8.10	508	508	216	80	170	22	71	315	28	640	630	400	1020	1380
	2	610	500	254	75	140	20	67.5	355	28	740	750	500	1080	1415
	4.6.8.10	610	500	254	95	170	25	86	355	28	740	750	500	1080	1485
355M	2	610	560	254	75	140	20	67.5	355	28	740	750	500	1080	1535
	4.6.8.10	610	560	254	95	170	25	86	355	28	740	750	500	1080	1605
	2	610	630	254	75	140	20	67.5	355	28	740	750	500	1080	1645
	4.6.8.10	610	630	254	95	170	25	86	355	28	740	750	500	1080	1675

 

()																						:mm
Frame	Flange size	Poles	Mounting Dimension																Figure size I
			A	B		D		F	G^a		K^b	M	N		R^d		T		AB^e		AD^e	HD*
80M	FF165	2.4.6.8	125	100	50	19	40	6	15.5	80	10	165	130	200	0	12	3.5	4	165	165	180	320	330
90S	FF165	Z.4.6.8	140	100	56	24	50	8	20	90	10	165	130	200	0	12	3.5	4	180	180	180	350	380
90L	FF165	2.46.8	140	125	56	24	50	8	20	90	10	165	130	200	0	12	3.5	4	180	180	180	350	410
100L	FF215	246.8	160	140	63	28	60	8	24	100	12	215	180	250	0	14.5	4	4	200	205	180	400	473
112M	FF215	246.8	190	140	70	28	60	8	24	112	12	215	180	250	0	14.5	4	4	245	230	200	420	520
132S	FF265	2.4.6.8	216	140	89	38	80	10	33	132	12	265	230	300	0	14.5	4	4	280	270	200	450	570
132M	FF265	2.4.6.8	216	178	89	38	80	10	33	132	12	265	230	300	0	14.5	4	4	280	270	200	450	615
160M	FF300	2.4.6.8	254	210	108	42	110	12	37	160	15	300	250	350	0	18.5	5	4	330	325	220	520	755
160L	FF300	246.8	254	254	108	42	110	12	37	160	15	300	250	350	0	18.5	5	4	330	325	220	520	795
180M	FF300	2.46.8	279	241	121	48	110	14	42.5	180	15	300	250	350	0	18.5	5	4	355	360	220	550	806
180L	FF300	246.8	279	279	121	48	110	14	42.5	180	15	300	250	350	0	18.5	5	4	355	360	220	550	806
200L	FF350	2A6.8	318	305	133	55	110	16	49	200	19	350	300	400	0	18.5	5	4	390	400	250	645	865
225S	FF400	4.8	356	286	149	60	140	18	53	225	19	400	350	450	0	18.5	5	8	435	450	250	690	913
225M	FF400	2	356	311	149	55	110	16	49	225	19	400	350	450	0	18.5	5	8	435	450	250	690	923
	FF400	4.6.8	356	311	149	60	140	18	53	225	19	400	350	450	0	18.5	5	8	435	450	250	690	953
250M	FF500	2	406	349	168	60	140	18	53	250	24	500	450	550	0	18.5	5	8	490	500	300	730	995
	FF500	4,6.8	406	349	168	65	140	18	58	250	24	500	450	550	0	18.5	5	8	490	500	300	730	995
	FF500	2	457	368	190	65	140	18	58	280	24	500	450	550	0	18.5	5	8	545	565	300	810	1047
	FF500	4.6.8	457	368	190	75	140	20	67.5	280	24	500	450	550	0	18.5	5	8	545	565	300	810	1047
280M	FF500	2	457	419	190	65	140	18	58	280	24	500	450	550	0	18.5	5	8	545	565	300	810	1122
	FF500	4.6.8	457	419	190	75	140	20	67.5	280	24	500	450	550	0	18.5	5	8	545	565	300	810	1122
	FF600	2	508	406	216	65	140	18	58	315	28	600	550	660	0	24	6	8	640	630	400	1020	1185
3 I	FF600	4.6.8.10	508	406	216	80	170	22	71	315	28	600	550	660	0	24	6	8	640	630	400	1020	1260
315M	FF600	2	508	457	216	65	140	18	58	315	28	600	550	660	0	24	6	8	640	630	400	1020	1305
	FF600	46.8.10	508	457	216	80	170	22	71	315	28	600	550	660	0	24	6	8	640	630	400	1020	1380
	FF600	2	508	508	216	65	170	18	58	315	28	600	550	660	0	24	6	8	640	630	400	1020	1305
	FF600	4.6.8.10	508	508	216	80	170	22	71	315	28	600	550	660	0	24	6	8	640	630	400	1020	1380
	FF740	2	610	500	254	75	140	20	67.5	355	28	740	680	800	0	24	6	8	740	750	500	108	1415
	FF740	4.6.8.10	610	500	254	95	170	25	86	355	28	740	680	800	0	24	6	8	740	750	500	108	1485
355M	FF740	2	610	560	254	75	140	20	67.5	355	28	740	680	800	0	24	6	8	740	750	500	108	1535
	FF740	4.6.8.10	610	560	254	95	170	25	86	355	28	740	680	800	0	24	6	8	740	750	500	108	1605
	FF740	2	610	630	254	75	140	20	67.5	355	28	740	680	800	0	24	6	8	740	750	500	108	1645
	FF740	4.6.8.10	610	630	254	95	170	25	86	355	28	740	680	800	0	24	6	8	740	750	500	108	1675

Packing

Certifications