438A Vibration Switches, Plate Mounted

A Full-Function, Switch-Selectable Vibration Monitor

The Vitec 438A Electronic Vibration Switch is an economical approach to accurate and reliable vibration protection for rotating machinery. Designed primarily for the OEM market but of equal value to end users, this device is a full-function vibration monitor that can be bolted directly to a machine. The rugged cast aluminum enclosure houses an accelerometer sensing element and the hardware required to qualify it as a true vibration monitor. Standard features include alarm and trip shutdown relays and signal outputs for local or remote metering purposes, and a NEMA 4 cast aluminum enclosure. An optional explosion-proof housing can be specified for use in hazardous areas.

Part No.Input Power Enclosure
53284-1120/220V AC (field selectable)NEMA 4
53284-2120/220V AC (field selectable)Explosion Proof
53284-324 VDCNEMA 4
53284-424 VDCExplosion Proof
53284-10120/220V AC (field selectable)NEMA 4X :Black
53284-1124V DCNEMA 4X :Black


Measurement mode


Frequency range

3 – 1000 Hz

Analog output

4 – 20 mA DC, proportional to full scale range

Input power

120/220V AC field-selectable or 24V DC (please specify when ordering)


2, field adjustable from 0-100% of full scale

Relay outputs

120/220V AC units: Solid-state triac, 10A max., 50mA min.
24V DC units: Solid-state transistor, 1A max.

Operating temperature

-25 to 160F (-32 to 71C)


NEMA 4 or Explosion-proof (Class I, Groups C & D; Class II, Groups E, F & G)(please specify when ordering)

Environmental rating

NEMA 4 – weatherproof


NEMA 4: 5 lbs (2.3kg)
Explosion-proof: 7.6 lbs (3.4kg)


NEMA 4: Flat surface, 4″ x 8″ (10.2 x 20.3cm)
Explosion-proof: Flat surface, 4.5″ x 9.25″ (11.4 x 23.5cm)

Conduit Entry

3/4 NPT

Optional accessories

Enclosure-mounted reset switch, P/N 53263-108

Remote meter in NEMA 4X Enclosure, 0-1 in/sec, P/N 79986-39A

Remote meter in NEMA 4X Enclosure, 0-3 in/sec, P/N 79986-39E

Field Adjustable Settings

Full scale range

0 – 1 in/sec or 0 – 3 in/sec

Alarm setpoint

0 to 100% of full scale range

Trip setpoint

0 to 100% of full scale range

Relay time delay

0 to 20 sec. per relay

Relay state

Normally de-energized (open below setpoint) or normally energized (closed below setpoint)

Relay configuration

Latching or non-latching

Relay inhibit

Inhibits relay operation during start-up or
machine maintenance

AC signal output

100 mV/g or 100 mV/in/sec


Ball Mills
Cooling lowers
General Purpose Rotating Machinery
Hammer Mills
Rolling Mills

User Benefits

  • Helps eliminate catastrophic equipment failures
  • Should your equipment vibration level increase, the 438A gives you notification, and can also shut down the equipment before major damage occurs.
  • Allows you to plan repairs in advance
  • Trending the vibration level enables you to detect changes in vibration, which allows you to schedule repairs coinciding with your normal maintenance schedule.
  • Compatible with predictive maintenance programs
  • The 438A is compatible with most data collectors, analyzers and online analysis systems. Analyzing the vibration signatures allows you to find specific causes of high vibration such as imbalance, misalignment and bent shafts as well as faulty belts, bearings and gears.
  • Eliminates false alarms
  • The 438A replaces mechanical vibration switches that can give false alarms or trips at machine startup, or when transient vibrations from external sources occur.
  • The 438A is designed to be field-configured to fit a wide variety of applications. When ordering the 438A you only need to specify the type of enclosure and the power input required.


  • Dual vibration level setpoints
  • Alarm and shutdown (“Trip”) contact closures are supplied, which activate when specified vibration levels are reached or exceeded.
  • Analog output
  • The 438A has a 4-20 mA DC analog output proportional to the full scale range, typically connected to a PLC, DCS or chart recorder.
  • AC signal output
  • An AC signal output, field selectable for 100 mV/g or 100 mV/in/sec, is standard. This output is available on a terminal block for connection to a customer-supplied remote connector.
  • Time delays and inhibit functions
  • Each relay has an adjustable time delay ranging from 0 to 20 seconds. An inhibit function is also included, which can be used to disable relay operation during start-up transients or machine maintenance.
  • Multiple configurations
  • The 438A comes in three different enclosure types: NEMA 4, NEMA 4X or explosion proof. It is also available with either AC (selectable 120/220) or DC (24V) input power.