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Motors and sensors go hand in hand. The EX range of motors already feature a wide range of sensors that deliver feedback on various parameters and, now, Parker has added a HIPERFACE DSL® encoder to the EX range of motors with explosion-proof enclosures. This makes it even simpler to control and monitor the EX servo motors using a Parker Servo Drive controller.
The High Performance Interface Digital Servo Link protocol runs on a standard RS485 connection to add the level of robustness needed to use it in almost any application. This includes industrial machinery, robotics and chemical and waste processing plants.
The main benefit of this technology is that it uses just one cable to deliver all of the motor control functions. This cable, which can be up to 100m long, can be bundled with the power cable, making it simpler to provide power and control to machines, robots and other equipment. With just one, smaller cable required, the umbilical for industrial machinery is lighter and more flexible, making them more reliable while delivering greater freedom of movement.
The EX motors, now equipped with the HIPERFACE DSL® interface, feature an explosion-proof enclosure and are certified for use in explosive atmospheres (CE/ATEX and IECEx). This includes use in atmospheres where explosive gases or dust are present.
As only one cable is needed, the EX motors have a lower total cost and provide a more reliable solution than a motor that requires two connections for control and feedback. These permanent magnet motors have a torque range of 1.75 to 35 Nm and come with a 2-pole resolver as standard and now an optional HIPERFACE DSL® encoder. This offers up to 20 bit resolution per revolution and a maximum of 4,096 revolutions in a multiturn system. Thermal protection is covered by the thermoswitches and thermofuses that are integrated into the motor's windings.
EX motors are compatible with the Parker Servo Drive (PSD) series, providing a complete solution for motor control in ATEX applications.
We can also offer a complete drive solution for ATEX applications with ETH the actuator and GXA gearbox (ATEX).
Finally, Parker’s well-known ETH electro cylinder range for explosive atmosphere is certified for use in explosive gas atmospheres (device group II, category 2G).
30 Jul 2020
Gold Cup - IE will help your Gold Cup pumps and motors work harder, smarter, and longer.
For example, Gold Cup - IE's predictive analytics can shorten downtime by enabling:
30 Jul 2020
As we introduced our Parker Sporlan webinar series we realized that we couldn't possibly answer all the questions in that short amount of time. We decided to create Climate Control blogs to answer some of the more pressing questions. This is the first of three blogs answering questions from our Supermarket Seminar Series: Metering Devices, TEVs.
TEV - Installation
Q: What if you can only mount the sensing bulb on a vertical suction line?
A: There are times when no other option is available. When one of those times happens, go ahead and install the bulb on the vertical suction line; however, this is a compromise. But how about installing an appropriate length of horizontal tubing at the evaporator outlet and before entering the trap for the riser? Now there is adequate room on a free-draining, horizontal length of tubing to install the bulb.
Q: If you must place the bulb on a vertical line. Does it matter how it is oriented, tail up or tail down?
A: Keep in mind, the vertical line is not the preferred location; however, there are times when no other option is available. If the thermostatic charge is a liquid type, the position of the capillary tube makes little to no difference concerning the bulb. If it is the MOP style charge, it might make a difference. If that is the case, it would be best to install the bulb with the capillary tube pointing toward the sky or "tail up" as you have suggested. Then, route the capillary tube so that it is physically above the bulb location and even insulate it as a final precaution.
Q: Should the sensing bulbs or the thermistors, in the case of electrically actuated-electronically controlled expansion valves (EEVs), be insulated on the pipe?
A: Yes, insulating the bulb or thermistor is good practice. This helps reduce external influences on the bulb or thermistor. It also helps to manage condensation.
Q: Do we need to apply thermal mastic between the sensing bulb and the pipe?
A: If you follow Sporlan's recommended installation practices, thermal mastic should not be required.
TEV - Internally & Externally Equalized Valves
Q: What is the max evaporator pressure drop before you need an external equalizer?
A: The pressure drop is rather small, in the range of 1 to 3 psid depending upon the refrigerant. Keep in mind, an externally equalized valve is necessary any time a refrigerant distributor is present in the system. One could substitute an externally equalized valve as a replacement for an internally equalized valve in just about any application. You simply need to install the equalizer line appropriately. The reciprocal is not true. If an externally equalized valve is required, an internally equalized version of the valve will not suffice.
Q: Why is the equalizing line connected downstream of the sensing bulb?
A: However unlikely, it is possible for an internal leak to develop in some thermostatic expansion valves (TEVs). In the event of a pushrod seal leak, refrigerant could be introduced into the low side of the system by way of the external equalizer line. This possible leak could influence the operation of the TEV by inadvertently cooling the sensing bulb and thus telling the valve to modulate to a more closed position. Positioning this connection downstream of the sensing bulb minimizes any interaction with the sensing bulb in the event an internal leak does occur in the TEV.
Q: Is the pressure tube typically connected after the distributor and before the coil?
A: If by "pressure tube," you mean the equalizer line, no, it must be installed and connected downstream of the evaporator. And better yet, it should be connected to the suction line downstream of the TEV sensing bulb. The distributor is on the inlet side of the evaporator between the TEV and the evaporator
Q: I've never seen an externally equalized valve with the second tube leaving the TEV. Are they uncommon?
A: No, externally equalized valves are not uncommon at all. In fact, most of the valves that Sporlan manufactures are externally equalized.
Q: Typically, I use an externally equalized valve for 4,000 BTU and up. Is that a correct approach?
A: It is a safe bet to utilize the externally equalized valve for almost any application. If the pressure drop across the evaporator coil is greater than 1 to 3 psid depending upon the system refrigerant, an externally equalized TEV is required. If there is a distributor in the system, an externally equalized valve is required.
Article contributed by Jim Jansen, senior application engineer, Sporlan Division of Parker Hannifin
Additional resources on HVACR Tech Tips:
29 Jul 2020