Njd Low-Speed Backstop for Belt Conveyor

Model NO.: NJD Highest Speed of Inner Race: 50r/Min-150r/Min MOQ: 1set Package: Wooden Case, Iron Case, Iron Cage, Frame Specification: ISO9001: 2008 HS Code: 8483409000 Rated Holdback Moment Te: 11000n.M-1750000n.M Standards: ASTM,DIN,Sha,Cema.etc Terms of Shipment: by Sea Trademark: OUNA Origin: Toncheng, China NJD Low-speed Backstop for Belt Conveyor

1. Structural features and operating principle
NJD(DSN) low-speed backstop(hereinafter referred to holdback) is a new type holdback device specially used for Belt Conveyor with big inclination and large conveying capacity.
This type of holdback is located using a bearing in which several shaped wedges are arranged in the raceway formed by inner race and outer race in a certain pattern so that it operates stably, the outer race is connected with two end covers, while the end covers are connected with the antirotation arm into an integral part through pins and the antirotation arm is limited by the fixed antirotation seat. When the motor operates normally, the holdback makes the wedges deflect by a certain angle through mechanics principle using the special geometry of the wedges so as to be in light contact with inner and outer race, thus reducing the coefficient of friction and improving the service life of the holdback. When the main motor needs to be shut down, the inner race of holdback reverses under the action of gravity of elevated material to drive the wedges to deflect and bring the inner race and outer race of the holdback to be wedged into an integral part so as to effectively prevent the motor from reversing. Therefore, this type of holdback is the most ideal non-reversing protector for conveying equipment such as large belt conveyor, Bucket Elevator etc.

2. Service environment
The ambient temperature for holdback operation is -20~50ºC, when the holdback is running, it will generate certain heat, so the ambient environment should be well ventilated, the temperature of the holdback running at allowable highest speed can reach 80ºC, in this case it is required to check the effect on the motor equipment and take appropriate temperature reduction measures, if necessary. When the ambient service temperature exceeds 38ºC or when it operates in open air, effective protective measures should be taken (for example, use ventilating equipment or cooling equipment etc.). Around the holdback it is not allowed to place corrosive chemicals for fear of damaging the holdback seal. 
 
3,Main technical parameters of low-speed backstop

Specification	Rated holdback moment (N.m)	Φ Max. hole diameter Φ (mm)	Highest speed of inner race (r/min)	Idle resistance moment (N.m)	Main installation dimensions									Max. mass (kg)
					B	C	D	L	H	E	F	h	ΦA
NJD(DSN)11	11000	110	150	15	100	60	270	110	425	/	/	/	/	77
NJD(DSN)16	16000	130	150	20	126	74	320	130	506	/	/	/	/	145
NJD(DSN)25	25000	160	150	32	140	80	360	140	612	/	/	/	/	198
NJD(DSN)40	40000	200	150	40	160	88	430	160	623	/	/	/	/	230
NJD(DSN)50	50000	220	100	70	200	100	500	230	820	110	50	70	35	385
NJD(DSN)100	100000	250	100	95	250	116	600	290	1000	120	55	70	40	696
NJD(DSN)130	130000	270	90	90	280	122	650	290	1100	120	60	80	40	812
NJD(DSN)200	200000	300	90	100	320	130	780	290	1300	135	60	80	45	1130
NJD(DSN)280	280000	320	90	130	360	140	850	320	1500	150	70	100	50	1480
NJD(DSN)330	330000	350	80	145	400	142	930	360	1600	160	70	100	55	1997
NJD(DSN)530	530000	420	80	200	450	146	1030	450	1800	180	80	120	60	3090
NJD(DSN)710	710000	450	80	225	500	160	1090	480	2000	210	100	120	70	3580
NJD(DSN)1000	1000000	510	70	260	560	170	1200	500	2200	230	110	150	80	4420
NJD(DSN)1350	1350000	560	60	320	630	180	1350	520	2400	250	120	150	90	5250
NJD(DSN)1750	1750000	620	50	400	710	190	1500	540	2600	270	130	160	100	7100

Notes: (1) It is recommended to adopt F7/h6 for the fit between the holdback hole and shaft (see Table 16) (if the user selects other fit, he shoud indicate this in the contract);
 (2) The holdback hole and shaft are mainly connected with flat key, and the dimensions of key and keyway should satisfy the provisions of GB/T1095-1979. The keyway for the holdback hole is fabricated according to the tolerance D10 in GB/T1095-1979 (see Table 16).
 (3) The length of shaft extension of the holdback should be equal to the length of inner race of the holdback as far as possible, its min. length should not be less than 5/6 length of inner race so as to ensure the strength of shaft extension and key. 

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Product Categories : Backstop for Belt