Nakakita NS286
Magnetic float level switch
Nakakita magnetic float level switches for tank and bilge-well level alarms (lube oil sump and gravity tanks, bilge wells, etc.). A float on a stem moves an iron core inside a sealed tube; a magnet outside follows it and actuates a micro switch (SPDT). The manual has one specification sheet per tag (service, fluid, specific gravity, set levels, action high/low), drawings, and instructions to adjust the on-off differential, the magnet stroke and micro-switch operating point, the operating level, installation, wiring, specific-gravity compensation and maintenance. Bilge-well switches work through intrinsically safe switch-operated relays.
Mga maintenance procedure
Adjusting the micro switch
- Turn the switch adjust screw so that the magnet holder rests 3.8 mm from its attraction position (free position). p. 76
- Set the switch operating screw so the micro switch changes over 2.3 mm from the free position. p. 76
- For two-switch units insert a 1.5 ± 0.1 mm gauge so the magnet cannot touch the pipe, then set No.1 and No.2 switches with a circuit tester so both actuate together. p. 87
- Lock the screws with red lock paint. p. 88
Changing the operating level
- Turn the knob to move the whole switch unit up or down within the ±10 mm scale. p. 88
- For larger changes move the upper or lower limit float on the stem, measuring from the flange face to the level band. p. 88
Yearly check
- Switch off the power, measure insulation resistance. p. 94
- Test with water and confirm actuation; remember the mark is for the design specific gravity, so with water it actuates lower. p. 94
- If the point deviates more than 5 mm, open it, wipe deposits off the tube and iron core and reassemble with match marks. p. 94
Mga maintenance interval
| Item | Kailan | Gagawin | Manual |
|---|---|---|---|
| Each level switch | every year | Independent function test; clean tube and iron core if the actuation point has drifted more than 5 mm | p. 94 |
Mga sira at ang dapat gawin
Technical specifications
| Body / float material | SS400 body, SUS304 float (typical sheet) | p. 3 |
|---|---|---|
| Contact | SPDT micro switch, AC 250 V 5 A / DC 250 V 0.3 A resistive | p. 3 |
| Insulation test | DC 500 V megger, over 100 MΩ | p. 3 |
| Withstand voltage | AC 1500 V for 1 minute | p. 3 |
| Set level accuracy | ±10 mm on sheet; setting precision within ±5 mm | p. 89 |
| On-off differential | about 10–30 mm standard; adjustable ±25 mm by range plates | p. 66 |
| Magnet free position | 3.8 mm from attraction position | p. 76 |
| Micro switch operating point | 2.3 mm from free position; differential 0.2–0.7 mm | p. 76 |
| Operating level change | ±10 mm by the knob on the switch | p. 86 |
Pinagmulan: manual ng gumawa na “EM-36 LEVEL SWITCH”, 95 pahina. Ang numero ng pahina ay ayon sa orihinal. Suriin ang manual sa barko bago magtrabaho.
Awtomatikong isinalin ang pahinang ito. Ang part number, code at pahina ay ayon sa orihinal.