2011Follow Focus forum
Power requirements for running a Preston focus motor and Bartech iris controller simultaneously from a single Arri camera power connector
15 years old. Gear and prices may have changed since.
What the thread found
- A single 3-pin RS power connector on an Arri Alexa can supply sufficient current to operate both a Preston focus motor and a Bartech iris controller simultaneously, as the combined draw remains within the connector's 2.2A maximum rating
- The Bartech BDR with M26VE iris control module draws approximately 500mA or less during normal iris operation
- A Preston DM2 focus motor with Bartech BDR draws between 163-625mA under normal operation at 12V, with peak stall current around 1.3A
- At 24V, the same Preston DM2 and Bartech combination draws between 230-619mA under normal operation, with peak stall current around 1.9A
Depends on
- Measurements were conducted specifically with a Preston DM2 motor; other Preston motor models may have different power requirements
- The data represents measurements taken in a controlled lab environment and may not account for all real-world usage scenarios
- Peak stall current of approximately 1.9A at 24V approaches the connector limit and leaves minimal headroom for other accessories