Siemens 6RA70 specifications 10-16, P077 Total thermal reduction factor, Temp = k1

	PNU		Description			Value range	No. indices	See
						[Unit]	Factory	Change
						Steps	setting	(Access /
							Type	Status)
	P076		Reduction of converter rated DC current		see column on left		Ind: 2	P052 = 3
*			i001:	Reduction of converter rated DC current (armature)			FS=100.0	P051 = 40
							Type: O2	Offline
	(G101)		i002:	Reduction of converter rated DC current (field)
			For the purpose of achieving a close match between the converter and
			motor, the converter rated DC current is reduced to the value entered here.
			The current value of the device rated DC is indicated in parameter r072.002.
			The following values can be set:
		10.0%, 20.0%, 33.3%, 40.0%, 50.0%, 60.0%, 66.6% 70.0%, 80.0%, 90.0%
			and 100.0%
			Note:
			If a load class is selected in parameter P067 which causes a reduction in
			the converter rated DC current, then the lower of the two parameter setting
			values is effective.
	P077		Total thermal reduction factor			0.50 to 1.00	Ind: None	P052 = 3
			The factor set in this parameter effects a reduction in the armature current		0.01		FS=1.00	P051 = 40
	(G101)						Type: O2	Offline
			limit (as defined by the setting in P075).
	(G161)
			The converter must be derated in the following instances:
			– Operation at high ambient temperatures:
			If the ambient temperature is higher than 45°C (on naturally air-cooled
			converters) or 35°C (on converters with forced air-cooling), the possible
			load capability of the converter decreases as a consequence of the
			maximum permissible thyristor junction temperature by percentage
			reduction "a" as specified in the table in Section 3.4, resulting in a
			temperature reduction factor of
			ktemp = k1
			– Installation altitudes of over 1000m above sea level:
			In this case, the lower air density and thus less effective cooling reduce
			the possible load capability of the converter to the percentage load "b1"
			specified in the table in Section 3.4, resulting in an installation altitude
			reduction factor of
			kaltitude = k2
			P077 must be set as follows: P077 = ktemp * kaltitude
			Note:
			A general reduction in the converter rated DC current (through appropriate
			setting of parameter P076.001) can be included in this calculation.
	P078		Reduction of converter rated supply voltage			i001: 10 to r071	Ind: 2	P052 = 3
			i001:	Rated input voltage converter armature		i002: 10 to r074	FS=	P051 = 40
	(G101)					[V]	i001: r071	Offline
			i002: Rated input voltage converter field
						1V	i002: 400V
			The rated voltage value of the power system actually used to supply the				except when
							r071 = 460V
			power section must be set in this parameter.
							then 460V
			This setting acts as the reference for the undervoltage, overvoltage and
							Type: O2
			phase failure monitoring functions (see also P351, P352 and P353) as well
			as for connectors K0285 to K0289, K0291, K0292, K0301 K0302, K0303
			and K0305

		NOTE
		If a SIMOREG converter is operated at a rated input voltage that is
		lower than its rated supply voltage, then the rated DC voltage specified
		in the technical data (Section 3.4) cannot be reached !
P079	Short pulses / long pulses, armature gating unit			0 to 1	Ind: None	P052 = 3
*	0		Short pulses (0.89 ms=approx. 16 degrees at 50 Hz) are output	1	FS=0	P051 = 40
					Type: O2	Offline
(G163)			on the armature gating unit.
	1		Long pulses (pulse duration up to approx. 0.1 ms before next
			pulse) are output on the armature gating unit (e.g. required in
			cases where field is supplied via armature terminals).

10-16	SIEMENS Energy & Automation
	SIMOREG DC Master Base Drive Panel Operating Instructions