Frequently Asked Questions
Q. What is a duty cycle?
A. Duty cycle is defined as (time on) / (time on + time off) per cycle. A lower duty cycle allows the motor to be run with as much as three times its continuous current rating for a short time period to produce higher forces than if the motor runs continuously.
Q. Do standard rotary motor electronics work with linear motors?
A. H2W Technologies' linear motors are designed to operate with most off-the-shelf controls and drives. Basically, linear motors use the same electric circuit as rotary motors. This applies to stepper, brush and brushless, and AC linear motors alike.
Q. Can a linear motor be mounted vertically or horizontally?
A. Yes. A linear motor provides the same performance when mounted vertically, upside down, or horizontally. However, a vertically-mounted linear motors must be counterbalanced.
Q. Can more than one stepper motor forcer be mounted on a stepper motor platen?
A. Yes, multiple forcers that move independently may be mounted on one platen, as long as they do not physically interfere with each other.
Q. Can more than one brushless linear motor moving coil (primary) assembly be used with a single magnet assembly (secondary)?
A. Yes, more than one coil assembly can be used in conjunction with a single magnet assembly as long as the coil assemblies do not physically interfere with each other.
Q. Does H2W Technologies make speciality motors for waterproof, vacuum, or clean room environments?
A. Yes, linear motors can be built for a variety of operating environments. To determine if a linear motors is suitable for a specific application, an applications engineer must review the application specifications.
Q. What types of linear motors does H2W Technologies make?
A. We offer of the broadest lines of linear motors in the industry, so customers are assured they get the best linear motor solution for their application. Our product line includes single-, and dual-axis linear steppers, single- and double-sided linear brushless and brush motors, non-commutated DC motors, enclosed positioning stages, single and cross roller bearing positioning stages, AC linear induction motors, polynoid linear actuators and position verification sensors. Also, new concepts in linear motion technology are continuously being introduced.
Q. Does H2W Technologies make solenoids?
A. H2W Technologies makes a polynoid AC linear motor and a non-commutated DC linear motor, both of which are similar to solenoids. The polynoid provides long stroke with constant force is both directions. (With a solenoid, force is only applied in one direction). Travels are only limited by end stops on the support rod. The non-commutated DC linear motor provides short stroke, up to 5 inches, with constant force in both directions.
Q. What are the advantages of a moving magnet actuator over a solenoid?
A. A moving magnet actuator is a DC motor which can be operated as a servo. This allows the device to move with extreme accuracy to any position throughout its entire stroke. The moving magnet actuator is well-suited for short stroke applications.
Q. What are the advantages of a linear motor over a lead screw?
A. The advantages of linear motors include higher velocities [>80 in/sec (>2 m/s)], non-wear moving part, free movement when power is off, no backlash because there are no mechanical linkages.
Q. What are the minimum and maximum sizes of linear motors?
A. H2W Technologies' linear motors are available in a variety of shapes and sizes beginning with 1/4" diameter. If a standard motor won't meet a customer's specific requirements, a custom motor can be built for the application.
Q. What type of feedback devices are available?
A. Feedback devices are not included with standard motors. However, a position verification sensor is offered for single and dual axis linear stepper motors and optical encoders are offered for closed-loop positioning systems.
Q. What happens if the system loses power of velocity feedback?
A. If a power loss occurs, the system loses all stiffness. So, if the payload is moving, it will continue to move until it hits a stop or until friction brings it to a stop. If the system is already stopped, it will not be affected. If the feedback loop is lost, it may lead to a runaway situation. This condition can be avoided with the use of soft and hard stops as well as braking systems.
Q. Do magnets ever lose their magnetism over time?
A. H2W Technologies' linear motors use rare earth magnets, which maintain their strength over time. However, when operating at high temperatures (>150°C), rare earth magnets can lose strength.
Q. What is cogging?
A. Cogging is a tendency of some linear motors to move in discrete distances rather than infinitely variable distances. The effect is a result of varying magnetic forces along the length of the motor.
Q. Does H2W Technologies offer full motion control solutions?
A. Yes, H2W Technologies can provide you with a full motion control solution including motor, bearing, amplifier, and motion controller.