120V Variable DC Power Supply

US Standard Testing & NEMA Simulation

Technical Overview

In the context of North American electrical engineering, the 120V variable DC power supply is a critical compliance instrument. Designed to encompass the full saturation range of the US mains standard (nominally 110V-120V), this class of power supply allows for the precise DC simulation of rectified mains voltage, essential for validating Universal Motors and older DC infrastructure. Furthermore, 120V serves as the definitive saturation point for 96V nominal battery systems. Engineers utilizing 120V supplies can safely perform equalization charging and capacity testing on these banks without the risk of over-voltage breakdown. The unit provides rigid voltage clamping to simulate grid swells (up to 127V) while maintaining a low noise floor for testing sensitive switch-mode power supply (SMPS) input stages.

Application Engineering Note

The 120V rating provides exactly the required headroom for US standard equipment without the safety hazards and cost penalties of 300V+ systems. It ensures precise regulation at the specific operating points of NEMA connected devices.

Compliance Standards

NEMA 5-15 (US Mains Simulation), UL 1012 (Power Units), IEEE 446 (Emergency Power Systems)

Primary Use Cases

Universal Motor Characterization (Torque/Speed)

96V Battery Bank Equalization & Cycle Testing

DC Contactor and Relay Life-Cycle Verification

Input Stage Validation for US-Market SMPS

Frequently Asked Questions (120V)

Can I use this 120V DC supply to test 110V rated equipment?

Yes. 110V equipment is typically designed to handle a tolerance range (often ±10%). A 120V variable supply allows you to test the device at nominal voltage (110V) and stress-test it at the upper limit (120V) to ensure reliability under grid swell conditions.

Is this power supply suitable for charging 96V battery banks?

Absolutely. A 96V lead-acid or LiFePO4 bank requires a charging voltage higher than its nominal rating to reach full capacity. A 120V supply covers the equalization voltage typically required (approx. 2.45V - 2.5V per cell for lead-acid), making it ideal for controlled charging cycles.

Does this unit simulate AC ripple?

No, this is a pure DC power supply designed to minimize ripple (<2mVrms). However, it can be used to simulate the 'rectified DC' stage of a power supply chain to test downstream DC-DC converters.

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Spec Sheet

REV. 2026

Output Ripple	< 2mVrms (Linear Topology)
Efficiency	> 88%
Cooling	Thermostatic Forced Air

Performance Index

Documentation

Access the full PDF Manual, Safety Data Sheet, and ISO Calibration Certificate.