Rexa FAQ

REXA Frequently Asked Questions

Q. What are the power requirements of my actuator?: A. The power requirements are as follows:

Single B-pump Power Module:

120 VAC, 1 phase, 50/60 Hz

200 VA

Single C-pump Power Module:

120 VAC, 1 phase, 50/60 Hz

800 VA

Dual C-pump Power Module:

120 VAC, 1 phase, 50/60 Hz

1600 VA

1/2 D-pump Power Module:

120 VAC, 1 phase, 50/60 Hz

2000 VA

Single D-pump Power Module:

240 VAC, 3 phase, 50/60 Hz

2000 VA

Dual D-pump Power Module:

240 VAC, 3 phase, 50/60 Hz

4000 VA

Other Voltages are available (+24 VDC, +48 VDC, 220 VAC, 440 VAC ).
Request TM-2 brochure for further details.
Q. What is the operating ambient temperature range of my actuator?: A. The operating temperature range is:

Request TM-19 brochure for further details.

Q. What cables are required between the control enclosure and actuator?: A. All actuators need a 3 conductor 18 AWG, shielded cable, designated the feedback cable. A module power cable is also needed. It is a 3 twisted pair, 1 twisted triad, non-shielded cable. Its gauge is dependent on distance between actuator and control enclosure. One module cable is needed for each power module. The D power modules two additional cables. Please refer to TM-8 recommended cable lengths for details.
Q. What is the maximum distance between control enclosure and actuator and what gauge cable is used?: A. All actuators, regardless of distance use an 18 AWG feedback cable.
The Motor Power Cable is designated as follows:

Please refer to TM-8 recommended cable lengths for details.

Q. What type of control signal input does the actuator accept?: A. The standard control signal is 4-20 mA DC. A pulse input of 24 -120 VAC/VDC is available as well as local and remote push-button control.
Q. What is the control signal input impedance of the PCP?: A. The Control Signal input impedance is 220 ohms resistive, with a series diode.
Q. What type of transducer is used for positioning the actuator?: A. A thin film, conductive plastic potentiometer is used as the position feedback element within the actuator. The potentiometer is rated for greater than 50 million cycles.
Q. What is the contact arrangement and contact rating of the electronic limit switches and alarm relay?: A. The contact arrangement is 2 Form C, and they are rated at 0.5A, 120 VAC resistive, 1A, 24 VDC, resistive.
Q. What is the contact arrangement and contact rating of the mechanical limit switches ?: A. The contact arrangement is 1 Form C, and they are rated at 3A, 24 VDC resistive, 10A, 120 VAC resistive for linear actuators. For rotary actuators, the arrangement is 1 Form C, 15A, 125/250 VAC resistive, 0.5A 125 VDC, 5A 24 VDC, resistive.
Q. What type of environment can the Control Enclosure and actuator be placed in?: A. The control enclosure and actuator are rated NEMA 4X, and are optional. Factory Mutual Approved for Class I, Div. II Groups C & D.
Q. How much oil is contained in the actuator and what type of oil is it?: A. The reservoir contains approximately 8 ounces. The amount of oil in the actuator is dependent on the size of the cylinder, (thrust and stroke or torque). The standard oil is Castrol 5W-50 synthetic motor oil.
Q. How often does the oil need to be changed?: A. Never. The actuator operates on a closed loop hydraulic circuit and never goes to atmosphere, thus preventing contamination. At no time is the oil exposed to extreme temperatures, hence there is no viscosity breakdown.
Q. If I need to add oil , how is it done?: A. All actuators are equipped with a Schrader valve on the power module for replenishing the oil reservoir. A standard grease gun is used, ( main spring removed), adapted to a Schrader valve chuck. Fill the gun with Castrol 5W-50 synthetic motor oil, clear the line of air, attach the chuck to the valve and pump the gun until the oil level indicator is fully extended and oil weeps from the pressure relief valve. The actuator does not have to be removed from service to add oil.
Q. What is required preventative maintenance?: A. The only preventative maintenance is to visually inspect the oil reservoir to confirm that there is oil in the actuator - approximately every 6 months.
Q. What type of mechanical override is available?: A. Mechanical override is available in the form of a de-clutchable handwheel attached directly to the motor shaft utilizing the normal hydraulic circuit. Also available is a 5/16" drill drive, a geared 5:1 hand crank, and hand-pump for larger units.
Q. What is the material of construction?: A. Anodized aluminum power modules, anodized aluminum and steel cylinders. Mounting hardware is generally carbon steel plate stock with stainless steel fasteners.
Q. What do I need to install a REXA actuator?: A. The mounting hardware is custom built to match up to your specific valve damper, or other device. Simply bolt the actuator in place, couple it to the valve stem (linear), or rotary shaft, and connect the supplied cable from the actuator to the control enclosure. Finally, setup the application via the SETUP PARAMETERS as directed in the Installation and Calibration Manual. Installation is complete.
Q. What spare parts are required with the REXA actuator?: A. Each part in the spare parts list is referenced to the Recommended Stocking Quantity through its critical index. This index is an estimation of the importance of a part to the operation of the actuator in a typical installation.
Q. With whom do I speak to inquire about spare parts ?: A. If the part number is available, contact your local sales representative or consult the factory and request to speak to "Spare Parts". If the part number is unknown, contact Bob Sass, Sales Engineer for assistance

Questions or comments about this web site should be sent to sales@whcinc.com. Last modified: 05/09/11

Questions or comments about this web site should be sent to sales@whcinc.com.
Last modified: 05/09/11