【单选题】
变压器绕组和铁芯在运行中会发热,其发热的主要因素是___。
A. 电流;
B. 电压;
C. 铜损和铁损;
D. 电感。
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答案
C
解析
暂无解析
相关试题
【单选题】
变压器一次侧为额定电压时,其二次侧电压___。
A. 必然为额定值;
B. 随着负载电流的大小和功率因数的高低而变化;
C. 随着所带负载的性质而变化;
D. 无变化规律。
【单选题】
油浸风冷式电力变压器,最高允许温度为___。
A. 80℃;
B. 95℃;
C. 100℃;
D. 85℃。
【单选题】
变压器呼吸器中的硅胶在吸潮后,其颜色应为___。
A. 粉红色;
B. 橘黄色;
C. 淡蓝色;
D. 深红色。
【单选题】
为了保证变压器安全运行,变压器室内必须具备良好的___。
A. 卫生设施;
B. 通风条件;
C. 照明条件;
D. 调温设施。
【单选题】
变压器铁芯应___。
A. 一点接地;
B. 两点接地;
C. 多点接地;
D. 不接地。
【单选题】
国家规定变压器绕组允许温升___的根据是以A级绝缘为基础的。
A. 60℃;
B. 65℃;
C. 70℃;
D. 80℃;
【单选题】
变压器铁芯采用叠片式的目的是___。
A. 减少漏磁通;
B. 节省材料;
C. 减少涡流损失;
D. 减小磁阻。
【单选题】
电除尘器的工作原理是___。
A. 利用烟速降低后,灰的自然沉降作用除尘的;
B. 利用灰的粘结性粘附在收尘板上进行除尘的;
C. 利用高电压产生的场强使气体局部电离,并利用电场力实现粒子与气流的分离;
D. 利用高电压产生的电解作用使粒子与气流的分离。
【单选题】
变压器的过载能力是指在一定冷却条件下,能够维持本身的寿命而变压器不受损害的___。
A. 额定负荷;
B. 最大负荷;
C. 最小负荷;
D. 平均负荷。
【单选题】
变压器油的主要作用是___。
A. 冷却和绝缘;
B. 冷却;
C. 绝缘;
D. 消弧。
【单选题】
变压器运行时,温度最高的部位是___。
A. 铁芯;
B. 绕组;
C. 上层绝缘油;
D. 下层绝缘油。
【单选题】
变压器套管是引线与___间的绝缘。
A. 高压绕组;
B. 低压绕组;
C. 油箱;
D. 铁芯。
【单选题】
绕组对油箱的绝缘属于变压器的___。
A. 外绝缘;
B. 主绝缘;
C. 纵绝缘;
D. 次绝缘。
【单选题】
油浸电力变压器的呼吸器硅胶的潮解不应超过___。
A. 1/2;
B. 1/3;
C. 1/4;
D. 1/5。
【单选题】
变压器中性点接地叫___。
A. 工作接地;
B. 保护接地;
C. 工作接零;
D. 保护接零。
【单选题】
变压器二次侧突然短路时,短路电流大约是额定电流的___倍。
A. 1~3;
B. 4~6;
C. 6~7;
D. 10~25。
【单选题】
绕组中的感应电动势大小与绕组中的___。
A. 磁通的大小成正比;
B. 磁通的大小成反比;
C. 磁通的大小无关,而与磁通的变化率成正比;D、磁通的变化率成反比。
【单选题】
油浸变压器温度计所反映的温度是变压器的___。
A. 上部温度;
B. 中部温度;
C. 下部温度;
D. 匝间温度。
【单选题】
变压器的使用年限主要决定于___的运行温度。
A. 绕组;
B. 铁芯;
C. 变压器油;
D. 外壳。
【单选题】
变压器低压线圈比高压线圈的导线直径___。
A. 粗;
B. 细;
C. 相等;
D. 粗、细都有。
【单选题】
同电源的交流电动机,极对数多的电动机其转速___。
A. 低;
B. 高;
C. 不变;
D. 不一定。
【单选题】
当一台电动机轴上的负载增加时,其定子电流___。
A. 不变;
B. 增加;
C. 减小;
D. 变化。
【单选题】
异步电动机是一种___的设备
A. 高功率因数;
B. 低功率因数;
C. 功率因数是1;
D. 功率因数是0。
【单选题】
异步电动机的转矩与___。
A. 定子线电压的平方成正比;
B. 定子线电压成正比;
C. 定子相电压平方成反比;
D. 定子相电压平方成正比。
【单选题】
感应电动机的转速,永远___旋转磁场的转速。
A. 大于;
B. 小于;
C. 等于;
D. 不变。
【单选题】
规定为星形接线的电动机,而错接成三角形,投入运行后___急剧增大。
A. 空载电流;
B. 负荷电流;
C. 三相不平衡电流;
D. 零序电流。
【单选题】
规定为三角形接线的电动机,而误接成星形,投入运行后___急剧增加。
A. 空载电流;
B. 负荷电流;
C. 三相不平衡电流;
D. 负序电流。
【单选题】
异步电动机的三相绕组加上三相对称电压后,在转子尚未转动的瞬间,转子上的电磁转矩___。
A. 最大;
B. 不大;
C. 近似于零;
D. 等于1。
【单选题】
异步电动机在启动过程中,使电动机转子转动并能达到额定转速的条件是___。
A. 电磁力矩大于阻力矩;
B. 阻力矩大于电磁力矩;
C. 电磁力矩等于阻力矩;
D. 不确定。
【单选题】
电动机运行电压在额定电压的___范围内变化时其额定出力不变。
A. -10%~+5%;
B. -5%~+10%;
C. -10%~+10%;
D. -10%~+15%。
【单选题】
如果一台三相交流异步电动机的转速为2820rpm,则其转差率S是___。
A. 0.02;
B. 0.04;
C. 0.06;
D. 0.08。
【单选题】
电动机连续额定工作方式,是指该电动机长时间带额定负载运行而其___不超过允许值。
A. 线圈温度;
B. 铁芯温度;
C. 出、入风温度;
D. 温升。
【单选题】
电动机定子旋转磁场的转速和转子转速的差数,叫做___。
A. 转差;
B. 转差率;
C. 滑差;
D. 滑差率。
【单选题】
当电动机的外加电压降低时,电动机的转差率将___。
A. 减小;
B. 增大;
C. 无变化;
D. 不确定。
【单选题】
当电动机所带的机械负载增加时,电动机的转差将___。
A. 减小;
B. 增大;
C. 无变化;
D. 不确定。
【单选题】
感应电动机的额定功率___从电源吸收的总功率。
A. 大于;
B. 小于;
C. 等于;
D. 变化的。
【单选题】
电动机铭牌上的“温升”指的是___的允许温升。
A. 定子绕组;
B. 定子铁芯;
C. 转子;
D. 冷却风温。
【单选题】
异步电动机在起动时的定子电流约为额定电流的___。
A. 1~4倍;
B. 3~5倍;
C. 4~7倍;
D. 7~10倍。
【单选题】
直流电动机在电源电压、电枢电流不变的情况下,它的转速与磁通___。
A. 成正比;
B. 成反比;
C. 不成比例;
D. 没有关系。
【单选题】
大型电动机的机械损耗可占总损耗的___左右。
A. 15%;
B. 10%;
C. 8%;
D. 50%。
推荐试题
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What new feature is introduced in NFS 4.1 on ESXi 6.5?___
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【单选题】
What configuration option would ensure that a virtual NUMA topology is defined on VMs having more than eight virtual CPUs?___
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【单选题】
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【单选题】
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【单选题】
Which port is used for vSphere HA agent-to-agent communication?___
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【单选题】
Which log file would assist in identifying an issue that occurred during the database export phase of a vCenter Server upgrade process?___
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【单选题】
Bidirectional CHAP is support by which storage initiator?___
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【单选题】
What is a pool of raw storage capacity that a storage system can provide to Virtual Volumes?___
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【单选题】
vSphere 6.5 DRS is now Network-Aware. Based on network utilization, when will DRS balance VMs?___
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B. DRS will balance VMs when Network I/O Control is enabled.
C. DRS will place VMs on initial boot for hosts that have network utilization lower that the threshold.
D. DRS will vMotion VMs when network utilization is higher than the threshold on a particular host.
【单选题】
A scripted upgrade of ESXi fails due to an incorrect parameter in the upgrade script. What file must the administrator modify to correct the problem?___
A. vmreconfig.pl
B. hostinfo.pl
C. ks.cfg
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【单选题】
A VM folder contains VM1 and VM2. Group A has permission to power on virtual machines, defined on the VM folder and its children. Group B has permission to power off virtual machine VM2. If a user is a member of group A and B, what action can the user perform?___
A. Suspend VM2.
B. Power off VM1.
C. Power on and power off VM1.
D. Power on and power off VM2.
【单选题】
The networking team has requested to have a dedicated network for iSCSI traffic. This task has been assigned to the vSphere Administrator. What is the VMware-recommended way to accomplish this?___
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B. Configure the right subnet.
C. Create a custom IP Stack.
D. Define a dedicated gateway for the iSCSI vmkernel.
【单选题】
To prevent possible failures or issues during a vSphere upgrade, which component should be upgraded first?___
A. ESXi Hosts
B. virtual machines
C. datastores
D. vCenter Server
【单选题】
What is the command for updating an ESXi host?___
A. esxcli software vib update –d /vmfs/volumes/Datastore/DirectoryName/PatchName.zip
B. esxupdate software update –d”/vmfs/volumes/Datastore/DirectoryName/PatchName.zip”
C. esxcli software update –d “/vmfs/volumes/Datastore/DirectoryName/PatchName.zip”
D. esxupdate software vib update –d /vmfs/volumes/Datastore/DirectoryName/PatchName.zip
【单选题】
A vSphere Administrator would like to identify which physical NUMA node their virtual machine is currently residing on. What esxtop metric would provide this information?___
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B. OVD_ND[x]
C. NRMEM
D. NHN
【单选题】
How can a vSphere administrator ensure that two virtual machines never run on the same datastore in a datastore cluster, while permitting the VMs to be load-balanced?___
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B. Configure a storage DRS VM override.
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D. RS for the VMs.
【单选题】
What is the VMware-recommended way to move a physical adapter out of Network I/O Control’s scope?___
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B. Add the vmnic to the Net.NetNiocAllowOverCommit parameter in Advanced System Settings.
C. Add the vmnic to the Net.IOControlPnicOptOut parameter in Advanced System Settings.
D. Move the vmnic to a different vmUplink port on the Distributed Switch.
【单选题】
A VM folder contains VM1 and VM2. Group A has permission to power on virtual machines, defined on the VM folder and its children. Group B has permission to power off virtual machines, defined on the VM folder and its children. If a user is a member of Groups A and B, what will be the user’s effective permission on VM1 and VM2?___
A. Power on
B. Power off.
C. Power on and Power off.
D. Reset.
【单选题】
Group 1 is granted console interaction on a VM folder. User 1 is granted no console interaction on the same VM folder. What will be the outcome if User 1 tries to access the console of a virtual machine?___
A. User 1 will not be able to access the virtual machines in the VM folder.
B. User 1 will not have access to the virtual machine console.
C. User 1 will have access to the virtual machine console.
D. User 1 will have console access only via the vSphere Web Client.
【单选题】
Which statement is true regarding the use of VMFS3 datastores with vSphere 6.5?___
A. VMFS3 datastores can be used but not created.
B. VMFS3 datastores can be neither used nor created.
C. VMFS3 datastores will be present but unmounted.
D. VMFS3 datastores can be created and used.
【单选题】
In the Exhibit, each VM has a 1GHz non-expandable reservation. If all VMs are powered on in sequence, what would be the outcome?___
A. VM4 cannot be powered on.
B. VM5 cannot be powered on.
C. VM6 cannot be powered on.
D. VM3 cannot be powered on.
【单选题】
vSphere 6.5 introduced MAClearning capabilities for VMware’s virtual switches. What three benefits will it provide? (Choose three.)___
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B. Reduced consumption of extra CPU cycles.
C. Increased network throughput.
D. Prevent packet flooding inside the vSwitch.
【单选题】
What is the default pathing policy for most active-active arrays?___
A. Fixed
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C. Dynamic
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【单选题】
Which command will show the iSCSI sessions on a ESXi 6.5 host?___
A. esxcli storage iscsi session get
B. esxcli iscsi session get
C. esxcli storage iscsi session
D. esxcli iscsi session list
【单选题】
Which of the following is not a parameter for traffic filtering or marking?___
A. virtual port ID
B. Protocol
C. Traffic Direction
D. DSCP value
E. Traffic redirection
【单选题】
A vSphere administrator wants to enable a virtual machine with Secure Boot, but in VM setting, Secure Boot option was not found under Boot Options. What could be the cause?___
A. The virtual hardware is not compatible.
B. The virtual machine has missing drivers.
C. The virtual machine OS does not support secure boot.
D. VMware Tools is not upgraded.
【单选题】
A virtual machine is connected on a distributed port group where the average bandwidth configured in the traffic shaping policy is 100 Mbps. The VM network adapter is configured with a reservation of 200 Mbps. What is the VM’s effective bandwidth?___
A. 200 Mbps
B. 100 Mbps
C. 150 Mbps
D. 400 Mbps
【多选题】
What are two reasons why a datastore in a Storage DRS cluster cannot enter maintenance mode?(Choose two.)___
A. Storage latency is too high to allow Storage DRS initiate Storage vMotion.
B. Storage DRS is configured for a VMFS3 datastore.
C. Storage
D. RS is disabled on the virtual disk.
【多选题】
What two methods are used to configure VMware vSphere Storage I/O Control shares and limits? (Choose two.)___
A. Assign shares and limits to VM virtual disks.
B. Assign shares and limits to datastores.
C. Assign shares and limits to Storage (DRS) clusters.
D. Assign shares and limits using VM storage policies.
【多选题】
ESXi 6.5 introduces VMFS6, which supports both 512e and 512n devices. What three configurations are supported when using these devices? (Choose three.) ___
A. Hosts with both 512e and 512n devices.
B. Storage vMotion between both 512e and 512n devices.
C. Datastore Extents spanned between both 512e and 512n devices.
D. Storage DRS clusters containing only both 512e and 512n devices.
【多选题】
A vSphere Administrator observes that the Primary VM configured with Fault Tolerance is executing slowly. After further investigation, it is determined that the Secondary VM is on an overcommitted ESXi host. What two methods will correct the problem? (Choose two.)___
A. Use Storage vMotion to migrate the Secondary VM to another datastore.
B. Use vMotion to migrate the Secondary VM to a different ESXi host.
C. Configure a CPU limit on the Primary VM which will also apply to the Secondary VM.
D. Turn off and turn on FT in order to recreate the Secondary VM on a different datastore.
【多选题】
Which two features require the use of Host Profiles? (Choose two.)___
A. Host Customizations
B. shared storage
C. Auto
D. eploy
【多选题】
What three processes on the vCenter Server Appliance (VCSA) does“vmware-watchdog monitor? (Choose three.) ___
A. vmware-eam
B. vmcad
C. vmware-vpostgres
D. vpxd
E. vsan-health
【多选题】
What three processes on the vCenter Server Appliance (VCSA) does“vmware-watchdog monitor? (Choose three.) ___
A. vmware-eam
B. vmcad
C. vmware-vpostgres
D. vpxd
E. vsan-health
【多选题】
Which two statements correctly describe VM-Host affinity rules? (Choose two.) ___
A. When there is more than one VM-Host affinity rule in a vSphere DRS cluster, the rules are applied equally.
B. After creating a VM-Host affinity rule, its ability to function in relation to other rules is predetermined.
C. When there is more than one VM-Host affinity rule in a vSphere
D. RS cluster, the rules will be ranked.
【多选题】
An administrator wants to enable proactive HA by moving virtual machines automatically if a hardware alert is triggered. What are the three required settings? (Choose three.)___
A. Set vSphere DRS Automation to Partially Automated.
B. Turn on Proactive HA.
C. Set the Proactive HA Automation Level to Manual.
D. Set the Proactive HA Automation Level to Automated.
E. Turn on vSphere HA and vSphere DRS.
【多选题】
If vCenter Server 5.5 installation has one or more services deployed remotely, which three services are relocated to vCenter Server 6.5 on upgrade? (Choose three.)___
A. vCenter Inventory Services
B. vSphere Authentication Proxy
C. vSphere Web Client
D. vSphere
E. SXi Dump Collector
【多选题】
What two debugging levels can a virtual machine be configured to? (Choose two.)___
A. Verbose
B. Debugging
C. Statistics
D. Trivia
【多选题】
What are three benefits of using a few large-capacity LUNs instead of many small-capacity LUNs? (Choose three.) ___
A. Better performance because there is less contention for a single volume.
B. More flexibility for resizing virtual disks.
C. Less wasted storage space.
D. More flexibility to create virtual machines without adding new LUNs.
E. Fewer VMFS datastores to manage.