Description

Application Scenarios

On a high-speed packaging machine’s cross-sealing axis, the servo motor must deliver a sharp torque pulse at the moment the sealing jaw closes, then return to a low-load follow profile—a classic pulse-duty cycle. A drive sized purely on continuous current would be over-specified and costly; one sized too small trips on overload during acceleration. The DST1405 occupies the sweet spot in the Digitax ST lineup: its 3× peak current capability (24 A for 0.25 s) covers the sealing pulse, while its 8 A continuous rating keeps the drive compact and the cabinet footprint minimal. When the machine builder later added an EtherCAT option module for tighter synchronization with the film feed axis, the same DST1405 hardware accepted the plug-in card without a drive replacement, preserving the original panel layout and wiring.

Parameter

Main Parameters	Value/Description
Product Model	DST1405 (Manufacturing part number: 3098-0070)
Manufacturer	Emerson / Control Techniques (now Nidec)
Product Category	Digitax ST Series Servo Drive, 400V Class
Input Voltage	380–480 V AC, 3-phase, 48–65 Hz
Continuous Output Current	8.0 A rms
Peak Output Current	24.0 A rms (3× overload for 0.25 s)
Power Rating (without line reactor)	3.32 kW
Power Rating (with line reactor)	3.65 kW
Switching Frequency	3 / 4 / 6 / 8 / 12 kHz selectable
Current Loop Bandwidth	1100 Hz
Speed Loop Bandwidth	160 Hz
Internal DC Bus Capacitance	220 μF
Built-in Brake Resistor	70 Ω
Safety Function	Safe Torque Off (STO), SIL 3 / PL e / Cat. 3
Protection Rating	IP20
Weight	Approximately 2.1 kg

Key Parameter Notes: The 8 A continuous / 24 A peak split is the defining specification—this drive is engineered for pulse-duty loads where average current is modest but acceleration demands are high. The 1100 Hz current loop bandwidth supports fast response on dynamic axes. The two option slots accept plug-in fieldbus and feedback modules, allowing protocol changes without replacing the base drive.

Technical Principles and Innovative Values

Innovation Point 1: Pulse-Duty Optimization Over Continuous Rating. The DST1405 is not simply the “biggest” Digitax ST; it is the model specifically positioned for applications where the load profile is intermittent and peak-dominated. Its 3× overload window (24 A for 0.25 s) and 2.5× window (20 A for 2 s) handle the acceleration spikes of packaging, labeling, and robot joint axes without thermal derating. Selecting a drive on continuous current alone would lead engineers to under-size for these profiles.
Innovation Point 2: Option-Slot Architecture for Lifecycle Flexibility. Communication and feedback interfaces on the DST1405 are plug-in modules, not fixed on-board ports. A machine shipped with analog command and resolver feedback can later switch to EtherCAT and a second encoder by changing cards—no new drive, no re-engineering of the panel cutout or mounting holes. For OEMs exporting to multiple regions with different fieldbus preferences, this reduces spare-parts variants and simplifies inventory.
Innovation Point 3: Integrated STO Without External Safety Relay. The DST1405 carries Safe Torque Off as a standard on-board function, certified to SIL 3 and PL e. In safety circuits where a simple “remove torque on door-open” function is sufficient, this eliminates the separate safety contactor and relay logic that traditional servo installations require, reducing panel space and wiring complexity.

Application Cases and Industry Value

A medical device manufacturer producing automated sample handling machines used DST1405 drives on the pipetting axis, where the motion profile consists of rapid index moves followed by extended dwell periods. The initial concern was whether a drive with only 8 A continuous rating could handle the acceleration spikes without nuisance trips. Testing confirmed that the 24 A peak window covered the acceleration phase with margin, and the drive’s automatic switching frequency reduction at standstill kept the heat load low during the dwell periods. When the company later decided to migrate from analog command to EtherCAT for tighter multi-axis coordination, the existing DST1405 units accepted the EtherCAT option module and resumed production without drive replacement. The maintenance lead noted that the option-slot design “saved us from buying a second generation of drives just to change the communication protocol.”