Schneider Electric 58 TRX Acceleration and Deceleration Ramp Profile, Torque Limit, Current Limit

Altivar® 58 TRX AC Drives

Drive and Motor Configuration Parameters

Acceleration and Deceleration Ramp Profile

The ramp profile for acceleration and deceleration is the gradual change of the output frequency from a speed reference following a linear or predetermined ratio that enables the ramps to be given an S- or U- shaped profile. For the ATV58 TRX controller, the selection of a ramp profile (linear, S, or U) affects both the acceleration and deceleration ramps.

An S-shaped ramp profile takes up mechanical play, eliminates jolts, and limits “non-following” of speed during rapid transient operation of high-inertia machines. They are particularly suited to applications involving materials handling, packaging, and personnel transportation.

U-shaped ramp profiles are ideal for pumping applications (installations with centrifugal pumps and non- return valves) because they improve control over valve operation.

The table below provides graphical representations of these two ramp profiles.

S-Shaped Ramp Profile

f (Hz)			f (Hz)		_Ramp.epsS
HSP			HSP
0		t	0		t
	t2			t2
	t1

U-Shaped Ramp Profile

f (Hz)	_Ramp.epsU
	f (Hz)
HSP	HSP

0			t	0			t
		t2				t2
	t1				t1

The curve coefficient is fixed, with t2 = t1 x 0.6 (t1 is the set ramp time).

The curve coefficient is fixed, with t2 = t1 x 0.5 (t1 is the set ramp time)

Torque Limit

A torque limit can be implemented in three ways on constant torque rated products:

•With the Torque Limit parameter. This parameter is factory set at 200% and can be adjusted from 0 to 200% of the drive controller’s constant torque rating.

•With a logic input and an associated torque limit (see Torque Limit by Logic Input).

•With an Analog Input (see Torque Limit by Analog Input).

Current Limit

This parameter can be used to limit the maximum motor current. This parameter is factory set at 136%, and can be adjusted from 25% to 136% of the drive controller’s constant-torque output current rating.

Switching Frequency

This function allows configuration of the drive output transistors’ switching frequencies. Refer to the drive controller rating table for continuous current ratings and associated switching frequency. The table below shows the available switching frequencies by type (parameter SFt) for each ATV58 TRX model.

Configurable Switching Frequencies

ATV58 TRX Models	LF Type (kHz)	HF1, HF2 Type (kHz)
ATV58•U09M2 to ATV58•D12M2	0.5, 1, 2, 4	8, 12, 16
ATV58•U18N4 to ATV58•D23N4
ATV58HD16M2X and ATV58HD23M2X	0.5, 1, 2, 4	8, 12
ATV58HD28N4 to ATV58HD46N4
ATV58HD28M2X to ATV58HD46M2X	0.5, 1, 2, 4	8
ATV58HD54N4 to ATV58HD79N4
ATV58HC10N4X to ATV58HC33N4X	0.5, 1, 2	4

ATV58 TRX drive controllers have an automatic feature that is used if the drive controller is intermittently used at the high end of its temperature rating and HF1 or HF2 switching frequency type is programmed. In this configuration, if the drive controller thermal state goes above 95%, the switching frequency drops into the LF: Low Freq. type range of 2 or 4 kHz depending on the drive controller rating (see the table above). When the thermal state cools to 70%, the switching frequency returns to the set value.

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