ABB MS325-16 Motor Protection Switch

ABB MS325-16 Motor Protection Switch

 

 

The ABB MS325-16 is a manual motor protection switch (manual motor starter) used for motor ON/OFF switching and combined overload + short-circuit protection in low-voltage motor circuits.

Product Information

• Brand: ABB
• Series: MS325 (MS series manual motor protectors)
• Part Number: MS325-16
• Type: Manual Motor Protection Switch (MMP / Motor Starter)
• Rated Current: 12.5 – 16 A adjustable range
• Poles: 3-phase (3P)
• Function: Manual switching + overload + short-circuit protection
• Mounting: DIN rail
• Standard compliance: IEC/EN 60947 series for motor control and protection

What it actually is

This device is a “manual motor starter with built-in protection”, meaning it combines:

• A manual ON/OFF switch
• A thermal overload protection mechanism
• A magnetic short-circuit protection release

So it replaces a combination of:

• circuit breaker + overload relay + manual switch (in small motor circuits)

How it works (simple)

• Turn handle ON → motor circuit is energized
• Overload occurs → thermal mechanism heats → trips device
• Short circuit occurs → magnetic release trips instantly
• After trip → handle moves to TRIP position → must be reset manually

System Role

Power supply
→ MS325-16 motor protection switch
→ motor (or contactor/motor circuit)

It is often used:

• directly with small motors
• or as upstream protection for contactor-based motor starters

Typical Applications

• Small 3-phase motors
• Pumps and compressors
• HVAC fans
• Conveyor systems
• Industrial machine motors
• OEM equipment motor protection

Key Features

• Adjustable current setting (12.5–16 A)
• Combined overload + short-circuit protection in one device
• Manual disconnect function (ON/OFF switch)
• Compact DIN rail installation
• High breaking capacity (industrial-grade fault protection)
• Fast tripping under short-circuit conditions

Advantages

• Saves panel space (3 devices in 1)
• No separate fuse required in many applications
• Fast response to short circuits
• Simple installation and operation
• Reliable motor protection solution for small systems

Important Notes

• This is not a PLC device or control relay
• It is not a signal switch (it switches power circuits)
• Must be correctly sized according to motor rated current
• Often used together with contactors in larger systems
• Cannot provide remote control unless externally wired

Precautions

• Set current dial strictly according to motor nameplate
• Do not use beyond rated short-circuit capacity
• Ensure correct phase wiring (L1/L2/L3)
• Not suitable for frequent manual switching under heavy load
• Must comply with motor protection coordination rules