5.8 Filters
The air filter is cleaned using a high quality degreasing agent. Clean the filter with compressed air and apply a thin layer of compressor oil.
The oil filter should be replaced as a single unit. The recommended replacement interval is every 1000 operating hours.
2.3. Special purpose plants and machines
Tachogenerator is a device which generates an electrical output directly proportional to the shaft speed. The voltage thus generated is fed to a speedometer for speed measurement and/or used as feed - back signal for controlling the speed of a rotating machine / equipment. In every automatic control system, since the system performance is directly related to the performance it becomes essential that the Tachogenerator must satisfy certain minimum requirements such as:
Linear
The rectified output voltage should be strictly linear with respect to the rotational speed
Output signal
The ripple content in the rectified output signal must be as low as possible
Temperature effect
Variations in ambient temperature should have negligible effect on the TG output
Long-term stability
Instability of output cause due to aging of parts, shift in magnetic circuits etc., should be minimum.
Unique features of Tachogenerator
ALINCO permanent magnet in the rotor assembly gives long term stable operation under varying ambient temperature.
Large number of poles (48) results in a high frequency output and hence good dynamic response, linearity and wide speed control, along with low ripple content in the rectified output.
Rotor and stator assemblies are encapsulated with epoxy resin to prevent any ingress of moistures, dust etc.
AC tachogenerators in 24 or 48 pole constructions with quasi-sinusoidal output of 30/ 50 Volts AC (rms) 1500 rpm
Stator assembly is housed in cast iron body to minimize magnetic interaction and consequent losses.
Grease filled, double shielded ball bearings are used for maintenance free operation.
Two mounting options-foot mounted and flange mounted.
Speedometer can be calibrated to suit the customer's requirements.
Compact and rugged construction provides longer life with excellent performance even under severe environments.
If required, TG can be supplied with rectifier unit, for DC operations.
Technical Specification
Type -Totally enclosed
Class of insulation -B
Voltage -30V / 50V AC and frequency 600Hz at 1500 rpm
Max. Load Resistance at Output - 600 Ω
No. Of poles - 48
Linearity - 0.5%
TACHOGENERATOR INTERFACE BOARD
Tachogenerator Interface Board
This is a small, inexpensive interface board that fits in the (optional) expansion connector of either Pro-120, VTX or earlier NCC controllers and is used with a tachogenerator to sense true motor speed to use in a closed loop control system.
It was originally developed for Dutch distributor - where it is used in an agricultural seedling planter - the space between the plantlets must be carefully controlled, hence the use of a tachogenerator to accurately control the speed of the machine.
The board should be ideal for most Robot Wars contestants: fitting tachogenerator feedback rectifies most of their known problems, including motor matching (inability to steer straight) and a tendency to bounce when load changes suddenly. However - the system will require setting up as a system, so does require some understanding.
The board available is physically matched to the Pro and NCC series controllers, but it is also a useful addition to other controllers.
Two versions of the board exist: one has a 9 way connector for the Pro series, the other has a 6 way, for the NCC series controllers. Note that the NCC tacho board will work electically with the VTX but is too large to fit into the boxed VTX.
DESCRIPTION: Model AT-4 V is combination of Tachogenerator and indicator in one piece for direct mounting on machines. The indicator is mounted on the tachogenerator through a suitable rubber mount so that machine vibration are not transmitted to the movement of the indicator. Tachogenerator front part can be made specially to suit replacement of imported speed indicators.
APPLICATIONS:
Direct mounting type speed indicator.
Local Indicator.
On the JT8D engine the inlet gearbox drives the N1 tachogenerator.