JDB type AC power grid insulation monitoring and alarm device can be used to continuously monitor the insulation level of the power, electric heating or lighting network of the three-phase neutral point ungrounded system of the ship or land AC power grid, and when the insulation of the power grid is abnormal and below the alarm value set by the instrument, it will emit an audible and visual alarm signal.
The JDB-II model can simultaneously monitor the insulation energy levels of two networks. By switching through the LW95 conversion switch, the insulation resistance energy of both networks can be read separately.
The alarm range of the instrument can be set in stages of 0.01-1.0M Ω, which is fully suitable for low insulation alarms in general power grids, and more suitable for insulation monitoring alarms in high insulation resistance applications such as reef blasting ships, coal mines, medical fields, etc. This instrument is small in size, light in weight, aesthetically pleasing in appearance, easy to operate, and has clear readings. This continuous automatic monitoring and alarm device is of great significance in preventing electrical fire accidents, ensuring the safe operation of the power grid, and achieving automated management.

Main technical indicators
1. The instrument can work reliably under the following environmental conditions: installation size
a. Environmental temperature: -10-55 ℃
b. Relative humidity: ≤ ≤ 95% with condensation
c. Tilt and sway: any angle
d. The impact vibration generated during the operation of ships or other equipment
e. An environment with salt spray, oil spray, and mold
2. Technical indicators
a. Instrument power supply voltage: 220VAC-10% -6%
b. Instrument insulation resistance: Cold state ≥ 100M Ω Hot state ≥ 50M Ω
c. Alarm accuracy:
The alarm level values are divided into
10K Ω, 30K Ω, 60K Ω, 100K Ω, 200K Ω, 500K Ω, 1M Ω, shore power
Accuracy: 10K Ω+5K Ω 30K Ω+5K Ω 60K Ω+10K Ω 100K Ω+10K Ω
200K Ω+20K Ω 500K Ω+50K Ω 1M Ω+0.1M Ω Shore power: Cancel instrument alarm
d. The maximum current that the instrument can pass through under the most unfavorable insulation conditions of the power grid is ≤ 10mA.
e. The power consumption of the instrument is ≤ 10VA.
f. Dimensions: 160X124mmX98mm. Hangout dimensions: 142X112mm. Hangout holes: 4X4mm (iron shell)
g. External dimensions 151mm × 107mm × 84mm Installation dimensions 139mm × 95mm Installation holes 4x5 (plastic shell)

Instructions for Use:
a. The JDB-II model uses terminal blocks for wiring,
1. Instrument press function:
a. Alarm setting: Press this key to reset the alarm value, which is displayed with the cursor.
b. Self check/Work "button: Check if the instrument is working properly. Press this button, the indicator light will turn on, and the instrument will enter self check mode. The meter reading will be 10K Ω and an alarm signal will be issued. Press the button again to return to normal monitoring mode.
c. Shore power indication: When a ship is anchored and using shore power, it is a three-phase neutral grounding system. At this point, the alarm level value needs to be set to "shore power", and the instrument alarm system will be cancelled.
2. Use of instruments:
a. After the wiring is correct, connect the power and the working indicator light will turn on, indicating that the instrument is in automatic monitoring mode. The meter reading is the insulation resistance value of the power grid at that time.
b. Set the alarm level value as needed, and when the insulation of the power grid is lower than the set value, the instrument will issue an alarm signal.
c. When the instrument does not alarm for a long time, in order to determine whether the instrument is working properly, press the "Self check/Work" button to perform a self check test. During self inspection, the instrument does not monitor the power grid. After the experiment is completed, it is necessary to return to a normal state.
d. This instrument cannot measure the insulation resistance of a tunnel network simultaneously with other instruments. Similarly, the same network cannot be measured simultaneously by two instruments, otherwise the readings will be inaccurate.
e. When the ship is anchored and using shore power, the alarm value should be set to the "shore power" position. Otherwise, the instrument will sound an alarm and the meter reading will be zero.
3. Maintenance and service:
a. During instrument maintenance, it is necessary to cut off the power supply to avoid accidents, and it is not advisable to open the casing to reduce instrument performance.
b. The various adjustment parts inside the instrument have been adjusted before leaving the factory. If adjustments are needed, they must be made by professionals and connected to standard resistors externally.
The factory implements lifelong service for instruments, with a warranty period of 18 months after leaving the factory. For repairs after the warranty period, the factory may charge a cost fee at its discretion

General technical parameters:

JDB-II AC power grid insulation monitoring and alarm device