Baldor Baldor, MN850 manual Top of Ramp Bypass Connection, 115/230VAC

NEMA 12/4 Installation When a NEMA12, NEMA4, NEMA4x OR IP65 enclosure is used, a separate Top of Ramp Bypass (or shunt) contactor must be connected in parallel with the soft–start control. This will allow a solid connection of the motor to the AC power lines and eliminate the heating effect caused by the SCR’s. At the completion of the start ramp (when full start voltage is obtained) a Bypass contactor is closed. This contactor is controlled by the “Top of Ramp” relay K2. This ensures that bypass will only occur when motor voltage equals the AC line voltage.

Figure 2-6 Top of Ramp (Bypass) Connection

115/230VAC				To AC Input
							To protect the control, be sure to add MOV protection.
Fuse	Neutral						Refer to Appendix D for additional information.
		X1		L1	L2	L3
		X2
		S1			Baldor
Note:	BC	S0					* BC	Bypass
					Digital			Contactor
Add appropriately rated		14			Soft–Start
protective device for AC		11	K1
		12
relay (snubber) or DC
relay (diode).		24		K2 is factory preset
		21	K2
		22		as the •Top of Ramp" function.
* External hardware not provided with control.				T1	T2	T3
See Recommended Tightening Torques in Table 2-4.
					To Motor

2-10 Installation MN850